# trig1 more question

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it is always true that if -1 ≤ x ≤ 1 then

cos(Arccos(x)) = x

Give an example showing that Arccos(cos(x))= x need NOT be true for all x

• trig1 more question -

if x = 300 degrees
cos x = 0.5
but
arccos(.5) = 60 degrees

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