SOLUTION: Find, to the nearest degree all of the values of x.. 2 cos^2 x + 2 sin x - 1 = 0

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Question 455472: Find, to the nearest degree all of the values of x.. 2 cos^2 x + 2 sin x - 1 = 0
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
Find, to the nearest degree all of the values of x.. 2 cos^2 x + 2 sin x - 1 = 0
..
2 cos^2 x + 2 sin x - 1 = 0
use following quadratic formula to solve for cos x:
..
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
..
a=2, b=2, c=-1
cos x=[-2±sqrt(2^2-4*2*-1)]2*2
cos x=(-2±√12)/4)
cos x=(-2±2√3)/4
cos x=-1/2±√3/2
cos x=-1/2-√3)/2=-1.366 (reject,(-1 < cos x < 1))
or
cos x=-1/2+√3)/2=.366
x=69º+2πn, 291º+2πn (n= any integer)