Question

Solve the given equation. (enter your answers as a comma-separated list. let k be any integer. round terms to three decimal places where appropriate. if there is no solution, enter no solution.) 5 sin 2θ − 7 sin θ = 0

Answer 1

5 sin 2θ − 7 sin θ = 0

we know sin 2θ = 2sinθcosθ

5(2sinθcosθ) -7sinθ =0

sinθ ( 10cosθ -7) =0

sinθ =0

θ = 2k*pi , pi + 2k*pi

cosθ = 0.7

θ = cos^-1(0.7) = 2k*pi + cos^-1(0.7)

θ = 2k*pi + cos^-1(0.7)

θ = 2k*pi - cos^-1(0.7)