SOLUTION: Cos^-1(sin 220)

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Question 1137181: Cos^-1(sin 220)
Found 2 solutions by MathLover1, ikleyn:
Answer by MathLover1(20850) About Me  (Show Source):
Answer by ikleyn(52817) About Me  (Show Source):
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Cos^-1(sin 220).


I read it as  arccos(sin(220°)).     <<<---===  I added the symbol ° (degrees)



Then  arccos(sin(220°)) = arccos(-sin(180°-40°) = arccos(-sin(140°)) = arccos(cos(90°+40°)) = arccos(cos(130°)) = 130°.



ANSWER.  Cos^-1(sin (220°) = arccos(sin(220°)) = 130°.