Question

The value of $\cos 1\cos 2\cos 3.......\cos 177\cos 178\cos 179$ is :

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

Answer 1

The correct option is A $0$

$Cos1\times cos2\times cos3\times ......\times cos179$

$=cos1\times cos2\times cos3\times .....\times cos90\times .....\times cos179$

$=cos1\times cos2\times cos3\times .....\times 0\times .....\times cos179$

$=0\times cos1\times cos2\times cos3\times .......\times cos179$

$=0$