Solve for 𝜃 if 0° ≤ 𝜃 < 360°. (Enter your answers as a comma-separated list.) cos 𝜃 2 − cos 𝜃 = 1

Answer 1

maybe the problem is cos^2(x) - cos(x) -1 = 0 IF so, then use the quadratic formula

cos(x) = 1/2 + (1/2)sqr(1+4) = (1 + or -sqr5)/2 = about 1.6 or -0.6

ignore the cosx that's greater than 1

cos(x) =-0.6 = - 3/5

x = 53 degrees for the reference angle

but x is in quadrant II or III since cosx is negative

x = 180-53 = 127 degrees or 180+53 = 233 degrees

x = 127, 233