trig
posted by paul c .
express 20sin theta + 4 cos theta as R sin(theta + alpha)
R sin(theta + alpha) =
R cos(alpha)sin(theta) +
R sin(alpha)cos(theta)
>
Rcos(alpha) = 20
Rsin(alpha) = 4
The xy coordinates of a point on a circle of radius R that makes an angle og alpha with the positive xaxis are with radius R are R cos(alpha) and R sin(alpha) respectively.
R follows from:
20^2 + 4^2 = R^2
If you divide the two equations you get tan(alpha)
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