How to differentiate a bracket raised to a power i.e. chain rule

Lets say the equation to be differentiated takes the following format y = (ax2+bx+c)n, to find dy/dx: (1) Make u equal the contents of the bracket, u=ax2+bx+c. (2) Substitute the contents of the bracket with u, y=un. (3) Differentiate y with respect to u, dy/du=nu(n-1). (4) Differentiate u with respect to x, du/dx=2ax+b. (5) Because dy/dx=(dy/du)(du/dx), we can derive. (6) dy/dx=(nu(n-1))(2ax+b). (7) Finally, substitute u with ax2+bx+c, dy/dx=(n(ax2+bx+c)(n-1))(2ax+b).

DF

Related Maths A Level answers

All answers ▸

By forming and solving a quadratic equation, solve the equation 5*cosec(x) + cosec^2(x) = 2 - cot^2(x) in the interval 0<x<2*pi, giving the values of x in radians to three significant figures.


Differentiate y=sin(x)/5x^3 with respect to x


Edexcel C3 June 2015 Q1: tan(x)=p, where p is a constant. Using standard trigonometric identities, find the following in terms of p. a) tan(2x). b) cos(x). c) cot(x-45).


What is the equation of the curve that has gradient dy/dx=(4x-5) and passes through the point (3,7)?