Processing Math: Done

From Förberedande kurs i matematik 1

The expression for the angle 2−v differs from 2 by as much as −v differs from 0. This means that 2−v makes the same angle with the positive y-axis as −v makes with the positive x-axis.

Angle v		Angle π/2 - v

Therefore, the angle 2−v has a y-coordinate which is equal to the x-coordinate for the angle v, i.e.

sin2−v=cosv

and from exercise c, we know that cosv=1−a2 ,

sin2−v=1−a2.