Question

Find the general solution of the equation 5cos2 θ + 7sin2 θ – 6 = 0

Answer 1

7sin^2A+5cos^2A-6=0
2sin^2A+5sin^2A+5cos^2A-6=0
2sin^2A+5(sin^2A+cos^2A)-6=0
2sin^2A+5(1)-6=0
2sin^2A-1=0
Sin^2A=1/2
SinA=1/√2
SinA=sin45°
A=45° here theta=A