Question

Please help fast!!
Solve the equation by first using a Sum-to-Product formula. (Enter your answers as a comma-separated list. Let k be any integer. Round terms to three decimal places where appropriate.)
cos 5θ − cos 7θ = 0

Answer 1

cos(a - b) - cos(a + b) =>
cos(a)cos(b) + sin(a)sin(b) - (cos(a)cos(b) - sin(a)sin(b)) =>
cos(a)cos(b) - cos(a)cos(b) + sin(a)sin(b) + sin(a)sin(b) =>
2sin(a)sin(b)

cos(5t) - cos(7t) =>
cos(6t - t) - cos(6t + t) =>
2 * sin(6t) * sin(t)

2 * sin(6t) * sin(t) = 0

sin(6t) = 0
6t = pi * k
t = (pi/6) * k

sin(t) = 0
t = pi * k

Most general answer: t = (pi/6) * k