(1.) f(x)=x^3+3x^2-2x+15. (a.) find the differential of f(x) (b.) hence find the gradient of f(x) when x=6 (c.) is f(x) increasing or decreasing at this point?

(1.) (a.) f’(x)=3x^2+6x-2

(b.) x=6 gradient=142

(c.) since f’(x)>0 at x=6, the function is increasing.

JE

Related Maths A Level answers

All answers ▸

Given f(x) = 3 - 5x + x^3, how can I show that f(x) = 0 has a root (x=a) in the interval 1<a<2?


What are logarithms?


When finding the turning points of a curve, how can I tell if it is a maximum, minimum or a point of inflection?


Sketch the curve y = (x^2 - 9)(x - 2)