Differentiate (1 Viewer)

[nsbrando]

ok i am struggling on this question,

Q. if y=x^4 - 2x^3 + 5, find dy/dx when x=-2

so far i got to:

f(x) = 4x^3
f(-2) = -32

what do i do next???

 

[Thief]

f '(x) = 4x^3 - 6x^2

f'(-2) = 4(-2)^3 - 6 (-2)^2
= -32 - 24
= -56