Question

If sin (7y) = cos (5y + 14), find y.

Answer 1

Explanation:

sin(7y)=cos(5y+14)=sin(90-(5y+14))=sin(76-5y)

7y=76-5y

12y=76

y=76/12=19/3

or

sin(7y)=cos (5y+14)=sin (90+(5y+14))=sin (5y+104)

7y=5y+104

2y=104

y=52