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How many values of $x$ with $0^\circ \le x < 990^\circ$ satisfy $\sin x = -0.31$?

 Dec 8, 2020
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arcsin  (-0.31)  ≈  -18°  = x

 

990/360   =  2.75  =  2 + 3/4   rotations

 

We  will have  two angles in each rotation  where  sin  x  = -0.31

 

360 - 18  = 342°

 

360 (3/4)  = 270°

 

So....in the last rotation, we only have  one  angle value  where sin x = -0.31

 

So....   2(2)  + 1  =   5  values of  x

 

cool cool cool

 Dec 8, 2020

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