How do you express $cos (\frac{3 π}{2}) \cdot cos (\frac{11 π}{8})$ $cos( (3 pi)/ 2 ) * cos (( 11 pi) / 8 )$ without using products of trigonometric functions?

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Answer 1 · 2016-09-03T23:37:46

Zero.

$cos (\frac{3 π}{2}) = 0$ $cos({3\pi}/2)=0$ , so its product with any real number is also zero.

How do you express cos( (3 pi)/ 2 ) * cos (( 11 pi) / 8 ) cos(3π2)⋅cos(11π8)cos( (3 pi)/ 2 ) * cos (( 11 pi) / 8 ) without using products of trigonometric functions?