Find the exact value of cos TT COS Sin Sin 16 16 16 16 Solut

Find the exact value of cos TT COS Sin Sin 16 16 16 16

Solution

We have

COS (A+B) = COS(A).COS(B) - Sin(A).Sin(B)

Comparing the given equation with the above equation ;

A =/16 and. B = 3/16

Therefore ,

COS(/16).COS(3/16) - Sin(/16).Sin(3/16) = COS (/16 +3/16)

= COS (4/16)

= COS (/4)

= 1/(2)