Why is the inverse of a gradient -1/x?

Because the value, x and its inverse, -1/x should multiply together to give -1. This is proof that two lines are perpendicular (or having the same magnitude of gradient but opposite signs +/- ).

SR

Related Maths A Level answers

All answers ▸

Expand the expression (1+3x)^1/3 up to the term x^3.


Differentiate with respect to x: 3 sin^2 x + sec 2x


Differentiate y=x/sin(x)


The function f (x) is defined by f (x) = (1-x)/(1+x), x not equal to -1. Show that f(f (x)) = x. Hence write down f ^-1 (x).