Question

The value of ${\cos }^2{0}^{\circ }+{\cos }^2{30}^{\circ }+{\cos }^2{45}^{\circ }+{\cos }^2{60}^{\circ }+{\cos }^2{90}^{\circ }$ is

• A. $\frac{1}{2}$
• B. $\frac{3}{2}$
• C. $\frac{5}{2}$
• D. $\frac{7}{2}$

Answer 1

The correct option is C $\frac{5}{2}$

Putting the value of cos from table,we have

$1+\frac{3}{4}+\frac{1}{2}+\frac{1}{4}+0=\frac{10}{4}=\frac{5}{2}$