Question

The value of cos (x/15) cos( 2x/15 ) cos( 4x/15 ) cos( 8x/15) is​

Answer 1

Step-by-step explanation:

its question based on product of cosine series and answer depend on angle so

if fist angle multiple of even*pi2 then answer is 1i

if first angle multiple of odd*pi then answer is -1

if first angle don't integer*pi then sine of last angle divide by product of sine of first angle and 2^n