Sin Y = Cos ( Y + 20° )

Question

I want the answer as soon as possible

Answer 1

In a right triangle the two acute angles add up to 90°. This means that the cosine of one angle is the sine of the other. So Y+Y+20=90, 2Y=70, Y=35°. There are other solutions but both the angles will not be acute.

Answer 2

Siny=cos(y+20°) Cos(90°-y)=cos(y+20°) 90°-y=y+20° Collect like term 90°-20°=y+y 70=2y Divide both sides by 2 Ans:35