Find the value of

cos1° cos2° cos3° ... cos89° cos90°.

Correct option is C

Given:

We are to evaluate the product:

​$$\cos1^\circ \cdot \cos2^\circ \cdot \cos3^\circ \cdots \cos89^\circ \cdot \cos90^\circ$$​​

Concept Used:
$$\cos90^\circ = 0$$​​

Solution:
Since $$\cos90^\circ = 0$$​, the entire product becomes:

​$$\cos1^\circ \cdot \cos2^\circ \cdot \cdots \cdot \cos89^\circ \cdot 0 = 0$$​