Derivatives
posted by Mark .
what is derivative of sin^2 (3x1)^2 ?
dy/dx (sin^2 (x))= 2 sin x cos x
dy/dx (3x1)^2= 6(3x1)
chain rule?
= 2 sin ((3x1)^2) cos ((3x1)^2) * 6(3x1)
Please help. Thank you

I'm not sure if this is correct. Can someone clarify thanks.

you are correct
Or, you could go on and say
sin (2(3x1)^2) * 6(3x1) 
I got 12 sin (3x1)^2 cos (3x1)^2 * (3x1) as my final answer. Is this in the correct simplified form ?

it is ok, but you can use
2sinu cosu = sin(2u)
to make it what I had:
6(3x1) sin(2(3x1)^2)
If you want to retain your original argument of sin and cos, then leave it as you had it. 
I have taken that into consideration; thank you!