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**magmagod** ok so i have been doing these trig equations for a while now...and i came up with this suspicious easy one..can anybody tell me if what im doing is right?

cos^2x = 1

took the square root of both sides and ended up with cos x = 1... then i took the inverse of cos (1) and came up with 0.. now im checking when cos is positive, and it turns out its in Q 1 and 4

so in Q1 its the same as the related acute which is 0 and in Q 4 its 2 pi - 0 which gives 2 pi...

is this right? is it ok to take the square root of both sides to remove the squared in the cosine??