 we will go beyond the abstract, how will latex go beyond the abstract, if you remove this end document there, why do not we put it little here. So, we will compile until here now. So, all this text instead of what I am doing is for the purpose of explanation in order to save time, this entire tech file is already written, thanks to our FOSSI employees. Now, I am just moving the end document lower and lower, so that more and more of the tech file will get compiled by PDF latex, this for our convenience, actually what you would have to do is you would have to type all this on your own terminal. So, there is this end abstract, after that we have gone to section, so there is a slash section, section name has come as introduction, then there is some content here, psi pi, how it is supposed to be pronounced is written here. So, there is actually no underline here, it is just you do not have to type an underline. So, after the break I will set the terminal, so that these things are more readable. So, there is open code, this open code again is different from this particular code which is closed code, the vertical code in latex is closed code. In latex you need separate symbols for opening and closing code, in Microsoft office, in open office, the same symbol will automatically work as open or closed, depending on first all odd occurrences of that symbol will be open, all even occurrences will be closed, but that is not how latex works, perhaps this is my only discontent with latex, that open or closed you have to tell it explicitly. So, with where is the symbol, this symbol is again above the tab key, above the tab key that symbol below the tilde, that symbol will mean open, if you put two of it will be double codes, double open codes and double closed code. So, why do not we compile this now, so here Glimpset sci-pi for C is the author, abstract is come, some font, this particular content has come in the actual font, this is the actual 10 point font, why 10 point, because notice that in our document class we did not give any arguments, optional arguments, that is why the default is 10 point, section has already got numbered as 1, section name has come here in bold larger font, then the main content, what has come after section comes like this, notice that let me make this little larger, this is open source of sci-pi itself, it is name of a package within python, how is it pronounced sci-pi, sci just like in sci or in scientific, sci for scientific, pi for python, pi. So, this is the content, do not worry about this content, why because you can type anything, what we should be worried about are these question marks, why did this question mark come, you will see a little later in this course, right now we are concerned with this, we are concerned with how to get certain things in italics, in different font, octave, these are all italics font, somebody has asked normally below abstract we have keywords, extremely important, how do you put the keywords, somebody has asked on chat, after the abstract we put keywords, extremely important comment, we will address this right away, that is another question on chat, I tried giving latex file name in command prompt, but I got an error in include graphics, why should I use PDF latex only, so the error about latex versus PDF latex, its significance in graphics that is something we will see a little later, for the specific person who asked about whether to use latex or PDF latex, because you use latex, graphics is giving a problem for that purpose, go to use package and just comment that line, use graphics, use package graphics, if you comment it, it will work, why because up to now anyway we do not have any figure, we do not have any graphics yet, so it will not matter, if you comment out that line, why use package graphics you have included, but you have anyway not use graphics features, that is why you can just comment out that line and do latex if you want, I would recommend that you use PDF latex, so that you are in sync with us, but then if you want to use latex, you please comment out that line, use package, let us go back here and see on the top, we commented out listings, because somebody said there is an error, graphics, please note actually there are two packages, graphics is the one, is the correct spelling actually, but graphics with the x is a another package, these are two different packages, whether graphics will work on latex or not, we are anyway not using a graphics features, we are not having any figure into our document, why do not we just comment it out now, when we have a graphics, when we have a figure in our PDF file or when we have a, when we want to include a figure into our document, then we have to use this package, if you use it unnecessarily, PDF latex seems to not give an error, latex now wants to, graphics certain packages work only for PDF latex, I was telling, so graphics with the x I think is such a package, color, color also is not anyway being used, you can comment that out if you want, no math symbol has been used, you can also comment that, listings give an error to somebody, that is why we ask that you just comment it out now, if it is not giving an error just let it be, so that same particular document has got created, this time without the graphics, graphics with the x, without that x, graphics package, we were, the next important question is how to insert keywords, so I am sure there is a way to put keywords, so let me just tell you what I do, I say keyword should be also be in bold, keyword 1, keyword 2, some people also put keyword between, separated between semicolons or semicolons, so we can always put it like this, because we want it to be in bold, we have put slash bf, bf stands for bold phase, how to put it, slash bf will suddenly make everything that comes after it in bold, but it will end up making the whole rest of the document bold, we do not want that, that is why we have enclosed it between curly brackets, curly brackets means that particular slash bf whatever you have put there will have its effect only between those curly brackets, its effect will not spill out, spill out to the rest of the document, so that is the meaning of curly bracket, if you just put slash bf you can check that the rest of the document will become bold phase, maybe rest of the document will not become bold phase, because look it may not come out of this environment, these environments are also like some borders, certain effects will not spill out, spill out of the environment, but whether that will spill or not you can check, meanwhile you can put this curly bracket that is certainly safe, if you do this then we have put this keywords, keywords has come, keyword 1, keyword 2, they have come in the same font as abstract, but they have come as bold because we put slash bf, rest of the document has not become bold either because we have enclosed slash bf between curly brackets or because at least curly brackets is certainly going to have this effect that the effect that bf will not make the rest of the document bold, environment abstract might also ensure that the effect does not go out, these are the things we typed, keyword 1, keyword 2, we forgot a space between here, so this is sticking, let us go back to our tech file, you can put a space, if it is the last character on that line and here is first character, then automatically space is left here, now keyword space has come here because end of the line character here, here, this is how one puts keywords, keywords typically if you want them to be in bold, this is how we can do it, if there is another way to do it you can try that also, you will have to look up on the net, at least I use this because this is really easy anyway, if it were really complicated I would have searched on the net, somebody has said even after typing end document after the make title, I am getting 7 pages after compilation, I strongly think you have not saved the document, open the document in an editor, open the tech file in an editor, whatever changes you make you have to save it, then only from the prompt when you do pdf latex, the latest, the saved version is all that will get compiled, if it is somebody is saying it is already saved, then you just open the document and see what is there remaining, there cannot be 7, 6 blank pages, I am sure that there is a problem at your end, you send the tech file to us, we will compile it, there has to be error at your end, I was just answering somebody's question on chat, what is the next thing we will see, section, we already saw introduction section, why are there no chapters, directly we have sections, because we are using document class article, in a article, in a conference paper article or a journal paper article, in a article you do not have section, you do not have chapters in an article, in a article you will directly have sections, when will you have chapters in reports, in books, in books certainly we have lots of chapters, if you are expecting to write your document in chapters, then most likely you are writing a report or a book, in that case you should go and choose document class book, because we are writing document class article, let us just verify this, we have to verify two things, this is my tech file, look I have said document class article, what I had not told was, I had not specified the font size, let us specify 12 pt, pt stands for point, 12 points, that is the way of indicating the size of the font, there is nothing latex about this, this is used in Microsoft windows environment also, the font size is specified in the points, pt, 12 pt means larger, why default is 10 points, I am saving it now, now document has become little larger font sizes, font sizes have become larger, also we are saying that directly we have introduction, because we have section names, so let us go back to this, section, when you say section, whatever comes in the curly brackets is the name of the section, inside section is where you will put sub section, then you can have sub sub section, any number of sub sub sub, any number of sections, sub sections, all these are automatically numbered, we do not have to give the numbers, it is very important that we should not be specifying the numbers, never specify any of these numbers, when will you specify the number, if you are going to say pi is equal to 3.1415, only those places you have to put the numbers, whatever numbers like section 1, section 2, those numbers latex will generate, latex will generate it and put the numbers automatically, not just for convenience, it is extremely important that you do not put the numbers, you will never put table numbers, you will never put equation numbers, you will not put chapter numbers, sub section numbers, figure numbers, these numbers you should not put yourself, why you should not put yourself, you might say I want to put the numbers, why should latex put, I will put it, this you might say this is some optional feature, no this is not optional feature, latex and only latex should put this, why, because if you decide some particular equation is equation 4.2, if you think that some particular section is section 1, later on if you put another section before this, then the number would have to be changed manually, but if you allow latex to automatically generate this number, then latex will compile it, that is when you have to compile it 2 times, that is when it will automatically know that this section has, is the second time it occurs, the second time the section command is called inside the document, it will automatically be section number 2, similarly sub section numbers, sub sub section numbers, all these numbers should come automatically only, please never make a mistake of putting equation numbers, section numbers, but when you are in the document when you are referring to, please see equation number 4.3, how do you know which number will get generated, how do you know if the number will change or not, what to do there we will vary little later today, for now section numbers are generated automatically, not just generated automatically, you should use only that automatic generation feature, never try to put the number yourself, never try to quote the generated number yourself, there might be a situation that you do not want the number to come, sometimes for appendix for example, you do not want appendix to be chapter number 18, it is appendix, there are certain sections for which you want the section title to come exactly like the title of any section comes large, bold, but you do not want the number to come, so if you put a star slash section star, then that number will get prevented, this is what we can see in our document. So, here is our section, here we will put a star, where are we putting the star, section star curly bracket introduction, this star is not like an optional argument, it is not to be put in square brackets, as soon as you put a star not just for section, in most places where number gets generated, if you put a star number will not get this, number will not get generated, number will be disabled there, so why do not we save this file, go back to the command prompt, let I get and look introduction has again come in big bold font, number has not come here, this is the important difference that has happened because we put a star, page number of course has got generated, this is a first page, there is only one page, any other, let us see the next thing in the slides, for longer documents we use report or book, that is where first you will have chapter, inside the chapter is where you will have sections, you will have chapter 1, chapter 2, then subsection, section numbers, section, if inside chapter number 1, you will have sections numbered as 1.1, 1.2, 1.3, this is exactly the way we want for a book or a report, this particular one, just a name that we had to choose for the first chapter, it could also be introduction, the first chapter typically we call introduction, chapter introduction, introduction in curly brackets, sections have some numbers, typically subsections we do not put numbers, if you want the subsections also to have numbers, then so this is like a depth, first top level is chapters, the book is organized into chapters, then the chapters are organized into sections, the sections are organized are suborganized, sub-suborganized into subsections, in that sense this is like depth, so there is one counter, there are various counters in latex, these counters are all automatic, we never have to know about it, until you have to set it, so if this sec num depth, if you think that subsection also should have numbers, then you can set counter the depth of the sec number, section numbering, the sec num depth is some particular counter that if you set 3, then the subsections will also get ordered, whether 3 or 4 or 5, this you can do trial and error, do not worry about these things, because these settings we do only once in a while, and that too for big projects, for books, chapters, how do you, had we not covered this in the slide, how would you do this, typically latex enough help is there on the net, and such things are there in any guide, any latex document guide, if you just do set counter, if you look for set counter pdf latex on Google, you will get all the counters, appendix comes at the end, they automatically do not have numbers, that is the meaning of appendix, unless you want appendix 1, appendix 2, then often there are also numbered as a 1, a 2, a 3, they are given as large size as sections, as chapters depending on whether it is article or book, slash appendix will do these things, table of contents extremely important, we want in our book for example, that the table of content is generated automatically, why because we do not know which particular chapter will begin in which page, even if you know now, tomorrow you include a figure, and suddenly the document has become little longer, and the chapters are beginning at different page number now. So, table of content is something that that is something that should be automatically generated, all the page numbers and all will come. So, what you can try later is you should just compile, and you should compile 2 times, why because first time it will find out what all section names are there, what all chapter names are there, and it is written on to one talk file, TOC file, TOC means table of contents, that same file name dot TOC is a extension, and when you recompile that time this table of content is actually built. So, table of content when you put that command into your tech file, when you put into your tech file, where will you put it, typically we want table of content to come after the title of the book, table of content we require only for books, we do not put it for articles, unless the article is very big, we do not put a table of content for the article. In the document class article if you put table of content what happens is something you can check yourself. Table of content is what we will put typically in a book or a report, if you have done document class report or document class book, table of content you will put after the title page, wherever you put the table of contents that is where the table of contents will appear, but it will appear only after you have compiled at least 2 times, why because the first time the TOC file is generated, first time latex will read line by line, find out where all which all page numbers the chapters are occurring, all that information is written into a TOC file, but table of content was anyway supposed to come in the second page of that book, first page was title page, second page, when it was generating the second page it did not know, where all the chapters will begin, that is why you have to recompile this, when I do recompile again again it is in general not essential, it is essential for example, when you want table of contents. Any book number, any section number, all this page figures, all the numbers come by themselves, if you want some, if you want the table of contents to in addition have some things, if you also wanted to have some extra information, then you can also use add contents line, this is some particular command that will tell you in the table of contents also add this, section intro, these are optional things, if you want all the sections that are generated to come, you can do this automatically, but some of them which are unnumbered, if you want to include them, this is how one does, references, bibliographies, how to do them that we will see later. Now, we have to come back to that particular topic that how did that word MATLAB, octave, how did those words appear in italics, those things is what we will see now, open code which is also called accent, that is the left code, that is the opening a code, close code which is also called apostrophe, when you want apostrophe, when you say Roshan's motorcycle, Roshan's motorcycle that apostrophe there you get by putting the vertical code, that is also the right code, the closing code. So, double code just use the same symbol 2 times, if you use the same symbol 2 times, they will occur very close to each other in the final document and it will indeed be a double code, yeah we can try this, we can try this in our tech file, here is our tech file, use sorry why do not I use open code for opening and close code for apostrophe, like Roshan's motorcycle, strange, as I said do not worry about the underlines, when you type underline then will not come, here is the document we have written, use open code for opening, yeah and close code for apostrophe or closing, like Prashan's, here notice how this is different from this, yeah we can make a larger font, this is open code, open code is different from this, here we have apostrophe, this see open and close are really different, this is one thing even though you do not have to specify open and close separately in most other packages, the font is not as nice as this, but then while you may or may not spend so much time admiring the font, please do not make a mistake of this opening and closing, yeah open code, open opening a code always use the open code symbol that is sitting right above the tab key, slash m that gives emphasis, emphasis to the text, yeah, will it be italics, whether it is italics or not we will see very soon, but if you are writing in normal Roman font, whatever you want in italics, whatever you want it to be in emphasized way for that you will use slash m symbol, yeah we will see that very soon, slash left, slash right center, these are things you can both use as a command and as an environment, yeah we can quickly see some examples of this now, so let us go back to this, here there was a slash m, slash m was opening there and it was closing here, yeah here is where m closes, emphasis from here up to here, yeah we can go for a smaller word, example of very emphasized text, if you want to emphasize something, then underline is not a good thing anymore, once you just put it in different font automatically that gets more attention, I have to use underline or bold is not the recommended way, that is if you want extremely lots and lots of emphasis, that is when you will make the font sizes larger or bold or underline, if you want just some moderate more emphasis then just use m, so let us write this compile this here, see here it has become very emphasized, this is the part in which off word, off word was outside the slash m curly brackets, then we started a slash m and everything this entire thing was given as an argument to the slash m command, so this is the recommended way to have a different font, why we should not use italics font, because some environment will automatically change the font, that time slash m will itself change the font, as long as the font of the few words are different, you are happy about this, somebody said font size except 10 or 12 could not be used with example documents, is there any way to increase it, yeah 10, 11, 12 these are the three things that are default, unless its presentation the other fonts are not available to the best of my understanding, we will quickly take a question from Rajlokshmi engineering college Chennai, please ask. Sir how to get the same font as latex as your name, latex itself, we will say latex, as I said T-A-X is like in technology latex, so latex itself has made a special command for itself, latex is written in some very nice font, are there any other questions before we start answering this, if please hold on let us just try this, so here if you do slash latex, slash latex is a command when you compile, when you do latex, when you compile it then you get this, yeah latex very soon we all will acknowledge that latex is very special and if it is so special, so look they have made a nice when you inside latex they have made this, that latex L will be big, A will be small, T again, E is slightly below X, yeah it is very hard to make these letters come in slightly different fonts, slightly above slightly below, in general these are hard, because it is so hard latex has made one such command for itself, latex will automatically become very nicely, so this is more like some we always write God with G capital, yeah like that, latex has made this nice symbol for itself, yeah any other questions about font size changes that we will see, but about latex it is very hard to do this, how to make this A go slightly above slightly below, these are things are, these are very much possible, but we will not see in this course, we will not see that in this course, these are things that are doable using picture, using picture begin picture end picture where you can put negative spaces go slightly above slightly below, but for latex if you want latex just use slash latex, let me just show the command L capital T capital X capital, only these three capital, yeah other two smalls, you might notice that first I had typed all small, so all the latex commands are very much case sensitive capital or small if you make a mistake in the commands it will give an error, it is unlikely that both capital and small are an error, look at this, so it is giving an error, yeah undefined control sequence, now that we have got this error, this is a good time for me to stop and tell, look we have not come to the command prompt, yeah this is where we will start discussing about this for the next few minutes, but notice that why it has given this error because latex command has not been typed correctly, what is incorrect about it capital small we have gone wrong, yeah. So, with that we will come back to this discussion about command prompt, so now coming to this problem that you when you are compiling then it said that when you are compiling on this particular line there is a problem, yeah it just says undefined control sequence, of course here also there is something undefined, actually this is the cause that there is some question mark coming again again, yeah how to resolve this we will see a little later, but notice that this is only a warning, you will pay close attention to what is only a warning and what is an error, because it is an error it says undefined control, it says an error and look it has ended with question mark, yeah that was not how we had actually our dollar prompt, our dollar prompt was this was our dollar prompt and when we do pdf latex it ends with the question mark, yeah whatever your prompt was it will end with the question mark, because it found something that is an undefined control sequence, yeah it is expecting for you to type something, if you do not know what to type press x and come back to the prompt x is what you will type to come back to the command prompt, now this is regular linux command prompt the terminal prompt about which we discussed in so much detail one week ago, but then as soon as you press x no pages of output, yeah of course there is still some output here that is because that this one was already compiled the previous time, this one was this is still existing, but now in the new compilation no pages of output have been created, why we why had no created it actually found an error and when it asked you the question mark when it asked you we pressed x, x is like exit what else could we do now again we try to latex there is an error actually it says undefined control sequence we are supposed to read all this, yeah all this reading is avoided if you use Kyle that is why I hate this integrated environments until you become used to all this, yeah Kyle also inside some information will be there for sure what one can do is so when it says undefined control sequence what are the various commands that are visible slash m is one command slash latex is another command one of these two commands do not exist they are undefined undefined control sequence either slash latex or slash m is undefined it is undefined that much hint is already being given, yeah luckily it was undefined control sequence so you know one of the commands do not exist that I did not remember that LT x have to be capital we do not have to remember so many commands as soon as you see that something undefined control sequence I knew it had to be with this capital small thing instead of pressing x one can press enter, yeah in spite of there being an error you press enter and now it has created output written on this, yeah we actually we did not remove the error the latex error the undefined control sequence we did not remove we just press enter instead of exiting we press enter and now output written let us go back to our output and see what has happened, yeah it has it has that latex has nothing has come on the screen so wherever that error was there there it will just ignore it will ignore whatever that command was supposed to do, yeah this to ignore that error you go ahead and compiling it is a extremely bad practice I see more and more of this with various students in our IT also that they do not remove the latex errors they just compile whenever there is an error for example they do whenever there is an error they just press enter if there are plenty of errors of course here there is only one error you press enter once it did not encounter any error let me tell you a shortcut if there are hundred errors you can press R R means it will go to so called running mode, yeah see ok entering non-stop mode latex provides you do not want to remove errors ok entering non-stop mode any further hundred modes and hundred errors it will not remove it will not stop for you of course if there is a error the document will not get compiled properly so let me warn you always you will keep track whether you have come back to the command prompt or not in other words whether you could do PDF latex without any errors so these are errors on the other hand there were some undefined references these are just warnings, yeah please pay close attention to what is an error what is a warning and in any of your assignments if you submit if you submit a tech file that does not even latex properly which is giving errors not just giving zero marks we are going to give negative marks let me warn you yeah please please do not tell us later that we did not warn you let me warn you again if you come to the prompt that means your latex perform without any errors coming to the prompt is top priority if it does not if your tech file that you submit does not latex properly does not latex properly means there are some errors you do not come back to the prompt when we will latex it see we will latex it here and see then we will give you negative marks ok so we are connected to Jaipur college cook us for a question from there please ask yes I have created the table of content file using add table of content but can you tell me the way how to get this file or how can read the file what command I should use on the latex prompt ok if I understand your question is that when you put slash table of contents into the tech file you compile it as I said you have to compile it two times then the table of contents has got generated if you have put slash table of contents it will get generated it will also come in the final PDF file it will come in the output already that we do not have to actually go and see the TOC file the TOC file we are not required to open and see what is written there it will have some information it will have what information this chapter begins on this page number this file this chapter begins on this page number this section begins on this page number this information is there in some nice formatted way I would recommend all of you to see it out of curiosity why only out of curiosity because the document that is getting generate the PDF file will anyway have table of contents page if there if there are many sections and chapters it will have two three pages of table of contents but the TOC file we do not have to open and certainly we should never edit the TOC file why we should not be editing the TOC file TOC file is automatically generated you spend lot of hours editing it you you think that some font size should be larger chapter name that comes in the table of contents page is not coming in good font you want to change the font you change all the font you do PDF latex once and the TOC file is again overwritten all your efforts in editing that file are gone based hence TOC file you can open and see out of curiosity editing it is totally useless unless you are sure this is the last time you will do PDF latex I have done in my in the past I didn't know how to change some particular font size so I went and edited the TOC file directly because I knew this was the last time if you are going to do PDF latex again it will override the TOC file any other question did I answer your question okay we are connected to Rajakshmi engineering college Chennai for a question from there so how can I add graphic the question is how can we add images and figures into our particular document this is indeed a very important topic we will cover it very soon it is there in our slides we will cover it very soon