Question

The value of ${\cos }^2{30}^{\circ }-{\sin }^2{30}^{\circ }$ is

• A. $\cos {60}^{\circ }$
• B. $\sin {60}^{\circ }$
• C. $0$
• D. $1$

Answer 1

Answer: (A)

$\cos {60}^{\circ }$

${\cos }^{2}30°-{\sin }^{2}30°$

$={\left(\frac{\sqrt{3}}{2}\right)}^2-{\left(\frac{1}{2}\right)}^2$

$=\frac{3}{4}-\frac{1}{4}$

$=\frac{1}{2}$

$=\cos 60°$

Hence, the answer is $\cos 60°.$