SOLUTION: cos 20 plus sin squared 0 equals 0, 0 degrees less than or greater to 0 less than 360 degrees

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Question 862730: cos 20 plus sin squared 0 equals 0, 0 degrees less than or greater to 0 less than 360 degrees
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!

cos(q) + sinČ(q) = 0,   0 ≦ q < 360°

           cos(2q) + sin2(q) = 0

We use the identity cos%282alpha%29=1-2sin%5E2%28alpha%29

1 - 2sin2 + sin2(q) = 0
    
        1 - sin2(q) = 0

                 1 = sin2(q)

                ±1 = sin(q)

            90° and 270° = q  
Edwin