Question #ffd93

1 Answer
Nov 15, 2017

See Below

Explanation:

sin (5x) cos (7x) — cos (5x) sin (7x) =-0.55

sin(5x-7x)=-0.55—>sin (A-B)=sinAcosB-cosAsinB

sin(-2x)=-0.55

-sin(2x)=-0.55—>sin(-x)=-sin x

sin(2x)=0.55

2x=sin^-1 0.55

2x=0.5823642379+2pin or 2x=2.559228416 +2pin

x=0.2911821189+pin or x=1.279614208+pin—>divide by 2

n=0, x=0.29, 1.28

S={0.29}