Find each derivative in simplest factored form

Hi, I'm having some trouble with these problems.

1. $\displaystyle f(x) = 3sin(cos4x)$

2. $\displaystyle f(x) = 5cos(sin(sin(4x^2)))$

3. $\displaystyle f(x) = sin^2(3x^2)$

4. $\displaystyle f(x) = cos^4(sin(cos(3x+2)))$

I'm not really sure what these 2 problems are asking me to do:

5. Write the equation of the tangent line to the curve $\displaystyle f(x) = 3cos2x$ at x = 0.

6. Write the equation of the normal line to the curve $\displaystyle f(x) = tan3x$ at x = pi/12

Any help is appreciated, thanks in advance!