Question

Value of $(\cos {60}^o\cos {30}^o-\sin {60}^o\sin {30}^o)$ is

• A. $0$
• B. $\frac{\sqrt{3}}{2}$
• C. $\frac{1}{2}$
• D. $1$

Answer 1

The correct option is A $0$

$\left(\cos {60}^0\cos {30}^0-\sin {60}^0\sin {30}^0\right)$

$=\frac{1}{2}\times \frac{\sqrt{3}}{2}-\frac{\sqrt{3}}{2}\times \frac{1}{2}$

$=\frac{\sqrt{3}}{4}-\frac{\sqrt{3}}{4}$

$=0$