Question

Suppose sin(θ)=1/4, where θ is in radians. Find exact values (as fractions, not decimal approximations) for the following.

(a) cos(π2−θ) =

Answer 1

Just by using associate angles identities, you have

`\cos\left((\pi)/(2) - \theta\right) = \sin(\theta)`

So, you also have

`\cos\left((\pi)/(2) - \theta\right) = \sin(\theta) = (1)/(4)`