Question

$\cos 1^{\circ }.\cos 2^{\circ }.\cos 3^{\circ }\dots \dots ..\cos {180}^{\circ }$ is equal to:

• A. 1
• B. 0
• C.
• D. -1

Answer 1

The correct option is B

0

$\cos 1^{\circ }.\cos 2^{\circ }.\cos 3^{\circ }\dots \dots ..\cos {180}^{\circ }$

$=\cos 1^{\circ }.\cos 2^{\circ }.\cos 3^{\circ }........\cos {90}^{\circ }........\cos {180}^{\circ }$
$=0$ [$\because \cos {90}^{\circ }$ = 0]