Question

If Sin (x-y) = cos [3(x+y)] so tan [2(x+y)] = ?

Answer 1

sin(x-y)=cos[3(x+y)]
sin(x-y)=sin[π/2 - 3(x+y)]
x-y = π/2 - 3(x+y)
x-y+3x+3y = π/2
4x+2y = π/2
2x+y = π/4

tan(2x+y) = tanπ/4 = 1