Posted by Henry on Tuesday, June 19, 2012 at 12:26am.
differentiate each function
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 don't 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 2:56am
c) 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 9:14pm
thank you