How do you differentiate f(x)=(5-x^2)(x^3-3x+3) using the product rule?

1 Answer
Dec 27, 2015

f'(x) = -5x^4 +24x^2 -6x-15

Explanation:

Derivative of product rule

Given " " " h= f*g

h' = fg' +f'g

The original problem

f(x) = (5-x^2)(x^3-3x+3)

f'(x) = (5-x^2) d/dx(x^3-3x+3) + d/dx(5-x^2)(x^3-3x+3)

=> (5-x^2)(3x^2-3) + (-2x)(x^3-3x+3)

Now we can multiply and combine like terms

=> (15x^2 -15 -3x^4 +3x^2) +( -2x^4+6x^2 -6x)
=> -5x^4 +24x^2 -6x-15