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January 28, 2015

January 28, 2015

Posted by **Henry** on Tuesday, June 19, 2012 at 12:26am.

a) y = cos^3x

b) y = sin(x^3)

c) y = sin^2 xcos3x

my answers:

a) y' = 3cos^2 x(-sinx)

b) y' = cos(x^3)(3x^2)

c) for this one, i dont know which one is correct. i got 2 different answers but i think they may be the same.. im not sure, i did it twice and got 2 diff answers, please let me know which is right or if they are both wrong. first answer for c: y' = 2sinxcosxcos3x + 3cos2x(-sinx)sin^2x or 2nd answer for c: y' = 2sinxcosxcos3x + (-sin3x)(3)(sin^2x)

thank you

- Calculus - please check my work -
**Damon**, Tuesday, June 19, 2012 at 2:56amc) y = sin^2 xcos3x

y' = sin^2 x (-3 sin 3x) + cos 3x (2 sin x cos x)

That is your second answer. Your first answer has a cos 2x in it which comes from where I do not know.

- Calculus - please check my work -
**Henry**, Tuesday, June 19, 2012 at 9:14pmthank you

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