in a problem like x = 2 sin ^2(t) and y = 3 cos ^2 (t)
can you use the trig identity to make it x/2 + x/3 = 1? to make it into an ellipse because i checked the back of my book for the graph and it was a line
You're a life saver, Sal! My professor in my calc 2 class went over an example one day.. He had spent about 10 minutes doing an example with trig involved, then brushed over it. Never really saw much in my book involving parameterizing trig parametric equations. ...And all of a sudden, BAM, first question on the exam is this. I got half right (did cos(arcsint)). 2 months pass and it's showing up again on a final exam review sheet. Found this video and suddenly I understand within 5 minutes!
@leoncio91 before they had no youtube but they hadless distractions,now we have youtube but a lot of distractions (facebook,xbox,psp,apple apps.....) .
So that's why angles are measured counterclockwise... Anyway, if we wanted to be more rigorous, I would say that even 3 points wouldn't be enough, for all we know the object could be moving 270 degrees clockwise every pi seconds. Do the equations agree with this possibility? I have yet to try them. Thanks for taking the time to make these videos, this has been said many times over but you are the greatest!
really great video! I'm going back to school in a month and i just want to say all your videos are great for refreshing my calculus. It helped me more than my professor did lol..
My mind tends to wander during lectures, as it does on these videos. But on youtube, I can rewind!
mellowmorgan92 1 month ago
takes too long to get to the effing POINT.
Kaminoeiennohigan 2 months ago
@Kaminoeiennohigan just be patient
MilitaryMan006 2 months ago
@wasdtomove924 it's a line because it ends up being x/2+y/3=1 for it to be an ellipse it would have to be x^2 /2 + y^2 /3 = 1
garrett92895 5 months ago
i feel weird with the ''arc sin''
but great channel
MrVargasesteban 6 months ago
Aiii luvz khanacademy. Helpt mi wit maii math
deathalert 10 months ago
@deathalert and your spelling..
anantnaik12 7 months ago
Wonderfully explained
diffusiventity 11 months ago
in a problem like x = 2 sin ^2(t) and y = 3 cos ^2 (t)
can you use the trig identity to make it x/2 + x/3 = 1? to make it into an ellipse because i checked the back of my book for the graph and it was a line
wasdtomove924 1 year ago
good video but i have a quick question
can you solve
x= 3sint
y= 4cost + 2
what conic section is it?
Victorisbored 1 year ago
You're a life saver, Sal! My professor in my calc 2 class went over an example one day.. He had spent about 10 minutes doing an example with trig involved, then brushed over it. Never really saw much in my book involving parameterizing trig parametric equations. ...And all of a sudden, BAM, first question on the exam is this. I got half right (did cos(arcsint)). 2 months pass and it's showing up again on a final exam review sheet. Found this video and suddenly I understand within 5 minutes!
NeoXC 1 year ago
nvm i got it.
lancevancedance 1 year ago
how about if one has "x=4cos(5t) and y=4sin(5t)". i dont understand what to do with that "5t" in the cosin function.
lancevancedance 1 year ago
rad!
loverofbeats 1 year ago
lol i almost feel bad for the people who went through college a few years ago, before youtube, and online help, etc good thing for us though haha
leoncio91 1 year ago 19
@leoncio91 before they had no youtube but they hadless distractions,now we have youtube but a lot of distractions (facebook,xbox,psp,apple apps.....) .
alitou001 6 days ago
Informative vid, thumbs up for this guy
robutubin 1 year ago
Am I the only one who is impressed by how well his ellipse fit on the first try?
aello465 1 year ago
omg best video ever!!!!
momo830223 1 year ago
I love you Sal!
woodenjaw 2 years ago
Thank you soooo much! i found this is the only way that I can learn, is having the lecture repeated. Thank you, and thanks Youtube!
MadCowCrazy916 2 years ago 13
This comment has received too many negative votes show
Isn't sin^2(y)=sin(siny)?
ABH1212 2 years ago
sin^2(y) = (siny)(siny) = (siny)^2
Wat114 2 years ago 6
So that's why angles are measured counterclockwise... Anyway, if we wanted to be more rigorous, I would say that even 3 points wouldn't be enough, for all we know the object could be moving 270 degrees clockwise every pi seconds. Do the equations agree with this possibility? I have yet to try them. Thanks for taking the time to make these videos, this has been said many times over but you are the greatest!
Biligerent 2 years ago
really great video! I'm going back to school in a month and i just want to say all your videos are great for refreshing my calculus. It helped me more than my professor did lol..
urpitsx 2 years ago 3
it is amazing how you can be interested by math!
Cr381v3 2 years ago 2
It's even more amazing how you can't!!!
kimboII 2 years ago
it wasn't me who put a thumb down on your comment... i just think it's amazing. in a good way. you don't have to be so offensive.. :P
Cr381v3 2 years ago
I wasn't trying to be offensive. Well a bit sarcastic maybe... But sarcasm is the closest relative of humor. :)
No worries... Good luck...
kimboII 2 years ago