How do you express cos(3π2)cos(5π4) without using products of trigonometric functions?

2 Answers
Feb 26, 2016

0

Explanation:

From knowledge of the graph of cosx , we know that

cos(3π2)=0

and cos(5π4)=cos(π4)=12

cos(3π2).cos(5π4)=0.(12)=0

Feb 26, 2016

It is equivalent to 0.

Explanation:

To express cos(3π2)cos(5π4), without using trigonometric functions, we should first find value of cos(3π2) and cos(5π4) separately.

cos(3π2) is equal cos(3π22π) or cos(π2), which is equal to cos(π2). But as latter is equal to zero,

cos(3π2)=0

Although, cos(5π4)=cos(2π5π4)=cos(3π4)=cos(π4)=(12)

cos(3π2)cos(5π4) will still be 0, as cos(3π2)=0