Question

What is the value of $\cos 1^{\circ }\cos 2^{\circ }\cos 3^{\circ }....\cos {90}^{\circ }$?

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

Answer 1

The correct option is B $0$

We know $\cos {90}^{\circ }=0$

Therefore, $\cos 1^0\cos 2^0\cos 3^0....\cos {90}^0=\cos 1^0\cos 2^0\cos 3^0....\times 0=0$
Thus the value of the expression is zero.