Question 1118107: Find the general solutions of sintheta=-1
I got: 180n-(-1)^n x 90
Why is the answer 180n+(-1)^n x 270?
My reasoning: don't you find the acute angle (if you put sin^-1(-1) in a calculator, you get -90)
I would appreciate any help and feedback
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! sin(theta) = -1
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the first occurrence of theta is -90(measuring clockwise) which is equivalent to 270(measuring counter clockwise)
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the answer assumes the angle is being measured counter clockwise
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if you used the -90 direction, then you have
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(2 * pi * n) - (pi/2), for n = negative integers, 0, positive integers(the set Z)
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