Question

Evaluate each of the following

$co{s}^2{30}^o+co{s}^2{45}^o+co{s}^2{60}^o+co{s}^2{90}^o$

Answer 1

$co{s}^2{30}^o+co{s}^2{45}^o+co{s}^2{60}^o+co{s}^2{90}^o$
= ($\frac{\sqrt{3}}{2}$)² + ($\frac{1}{\sqrt{2}}$)² + ($\frac{1}{2}$)²+0

=$\frac{3}{4}$ + $\frac{1}{2}$ + $\frac{1}{4}$ + 0

=$\frac{3}{2}$