Trigonometric Integrals Example 1

[MrAbhilash02]

thank u u r so helpful



[TheIntegralCALC]

@MrAbhilash02 Glad you think so! :)

[gravisan]

can you pls make a video showing why int(cos(x) dx) = sin(x)?

[IndividualParties]

@gravisan

Well that's kind of basic and doesn't require any integration techniques. It just follows from the fact that the derivative of sine is cosine. Always differentiate the result to see if you get the integrand.

[tommie997]

You are a life-saver! Thank you for giving up your time to help all the struggling calculus students around the world!

[TheIntegralCALC]

@tommie997 I'm happy to help! Thanks so much for the comment. :)

[FunkyMexicanBassist]

Where did the du go after the integral of cos(u)? That's something I am trying for the love of God figure out... I thought du = 2xdx?? Please helpppp

[TheIntegralCALC]

@FunkyMexicanBassist The du disappears once you integrate (evaluate the integral). The integral of cos(u)du is sin(u). Therefore, you replace the entire integral, including the du, with sin(u). Once you take the integral sign away, the du has to go away also. Hope that helps! :)

[mpatt79]

@FunkyMexicanBassist I always preferred to look at it like this: when I "take" the integral, I must also "take" away the dx - or in this case, du.... good luck

[DelGeeZee]

i am the integral master!!!! holla!

[poopta]

I love you almost as much as I did my 11th grade Calculus teacher

[TheIntegralCALC]

@poopta hopefully that means a lot! :)

[1MoneyTalks]

Isn't cosX dx = -sinX ?

[TheIntegralCALC]

@1MoneyTalks The derivative of cos(x) is -sin(x), but in this video, we're taking the integral of cos(x), which is sin(x). Hope that helps! :)

[1MoneyTalks]

2:53 => airplane passing by.

[dhpackr]

I'm a non traditional student who has been out of school for 25 years. Been watching your vids all week, got my Calculus final today......hopefully the vids will help my grade.

[TheIntegralCALC]

@dhpackr I hope your final went GREAT!! :D

[diegeeleel]

I don't care what they say about the way you hold the pen. I have a calculus test tomorrow and you helped me. therefore. I love you.

[TheIntegralCALC]

@diegeeleel Awwww! I love you too! Good luck on your test, I hope you do GREAT!!! :D

[slaughterkill93]

This is so great, cramming for calculus quiz's on Youtube. Thanks!

[TheIntegralCALC]

@slaughterkill93 You're welcome! Hope your quiz goes well :)

[tsukominako]

Very helpful and very easy to understand!!!

Thank You

[TheIntegralCALC]

@tsukominako You're welcome! :)

[redrum41987]

shmeeper

[sxj016]

You are the Goddess of Calculus...we are not worthy.

[TheIntegralCALC]

@sxj016 Lol! Thanks!! Glad it helped!!! :D

[Lukawa345]

Thanks for the tips.. love it.. 

[strangercandy]

wow that was great plus u r so beautiful will u marry me

[corzocl]

@strangercandy creeper