Help needed in determining sin(x +y).

Question

Question:

 

Determine sin(x + y) when sin(x) = 1/3, -π/2 ≤ x ≤ π/2 and cos(y) = -1/4, π ≤ x ≤ 2π

 

 

Much appreciated if anyone might be willing to help me out on this one.

Answer 1

Use formula

sin(x+y)=sin(x) cos(y)+cos(x)sin(y). (A)

sin(x) and cos(y) are know know.You have to find sin(y) and cos(x) and plug in into (A).