Question

The
value of $\cos 1^{\circ }\cos 2^{\circ }\cos 3^{\circ }.....\cos {179}^{\circ }\text{is}$

• A. $0$
• B. $2^n$
• C. $2^{n-1}$
• D. $2^{n-2}$

Answer 1

The correct option is A $0$

$\cos 1^o\cos 2^o\cos 3^o.....\cos {179}^o$

$\cos 1^o\cos 2^o....\cos {89}^o...\cos {179}^o$

$\because \cos {90}^o=0$

$\therefore \cos 1^o\cos 2^o....\cos {89}^o\times 0\times .....\cos {179}^o$

$=0$