What are Two of the solutions of cos(x/2)= -√2/2?

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Answer 1 · 2018-04-30T00:18:29

Within one period #(0 < x/2 < 2pi)#:

#x=(3pi)/2, (5pi)/2#

.

#cos(x/2)=-sqrt2/2#

Negative cosine values indicate that the angle is either in quadrant #II# or quadrant #III#.

From the unit circle:

#x/2=(3pi)/4, (5pi)/4#

#x=(3pi)/2, (5pi)/2#