Find the inverse of the general 2x2 matrix A= ([a, b],[c, d]) when does this inverse exist?

This is a typical further maths question, doing it correctly is a matter of carrying out a two-step process. 

Start by finding the determinant of the matrix,

det(A)=ad-bc

Then swap the entries a d and negate the other entries. After dividing by the determinant the inverse of A is given.

A^-1=1/(ad-bc)([d -b],[-c, a]).

LR

Related Further Mathematics A Level answers

All answers ▸

If 0<x<1, find the following sum: S = 1+2*x + 3*x^2 + 4*x^3 + ...


A=[5k,3k-1;-3,k+1] where k is a real constant. Given that A is singular, find all the possible values of k.


How do you sketch the graph of y=(x-1)/(x+1)?


Using z=cos(θ)+isin(θ), find expressions for z^n-1/z^n and z^n+1/z^n