Posted by **LISA** on Monday, February 27, 2012 at 12:16am.

i don't understand this problem

Let F(x)=f(x^4) and G(x)=(f(x))^4. You also know that a^3=2, f'(a)=13, f'(a^4)=15. Find F'(a) and G'(a).

- COLLEGE CALCULUS. -
**MathMate**, Monday, February 27, 2012 at 9:16am
F(x)=f(x^4)

Using the chain rule,

F'(x)=f'(x^4)*(d(x^4)/dx)=f'(x^4)*3x^3

substitute x for a and all the numerical values supplied to find F'(a).

Similarly, G(x)=(f(x))^4

Apply the chain rule successively,

G'(x)=(d/dx)(f(x))^4)

=4f(x)^3*f'(x)

So G'(a)=4f(a)^3*f'(a)

Although f'(a) is known, it is not clear to me how we can find f(a).

## Answer This Question

## Related Questions

- College Math II - Solve each problem. Find the quotient and remainder when x^2...
- College Math II - Solve the problem. If a manufacturer charges q dollars each ...
- calculus - I don't understand how to do this problem find s(t) for a(t)= 3t^2, ...
- Math - I am in Calculus and am currently learning how to find the Area of a ...
- COLLEGE CALCULUS. HELP! - i dont know how to start this problem. i dont like cos...
- Calculus AP need help! - i still understand this problem If x^2/25 +y^2/49=1 and...
- College Algebra - Hello - I am stuck on this problem and I'm in serious need of ...
- Calculus: Integral - I don't understand how to do this one integral problem that...
- Calculus - Find the derivative of y=xe^-x^2. Is the x being multiplied by (e^-x^...
- Math - Find the equation of the straight line joining a)(4, 4) and ( 2, 0) b)(3...

More Related Questions