The common equation of C is xsina ycosa Sina = 0, which makes a vertical line of C through the origin. Why is the vertical foot (Sina ^ 2, - cosasina) | Math enthusiast | Mathematical art

The common equation of C is xsina ycosa Sina = 0, which makes a vertical line of C through the origin. Why is the vertical foot (Sina ^ 2, - cosasina)

y=xsina/cosa-sina/cosa
Slope Sina / cosa
Vertical, the slope of the vertical is - cosa / Sina
Over origin
So y = - cosax / SiNx
Substituting y = xsina / cosa Sina / cosa
We find that X and y are x = Sin & # 178; a, y = - sinacosa

If sinacosa = 1 / 8 and π / 4 is less than a and π / 2, what is the value of cosa Sina?

From sinacosa = 1 / 8
（cosa-sina)^2=(cosa)^2-2sinacosa+(sina)^2
=(cosa)^2+(sina)^2-2sinacosa
=1-2*1/8
=3/4
So cosa Sina = (3 / 4) open root = 2 / 2 root 3
Or equal to the root of negative 2 / 3
Because π / 4 is less than a, and π / 2 is less than a, cosa can be obtained

High school mathematics sin2a / Sina =?

sin2a=2sinacosa
So sin2a / Sina = 2cosa

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