# Precalculus

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Given r = 10 cos θ

If you sketched an angle of θ = 150 degrees, what quadrant would it be located in?
It's either the first or second... I think second?

Multiply both sides of r = 10 cos θ by r. Transform the resulting equation into Cartesian coordinates.

• Precalculus -

second is from 90 to 180 degrees

r^2 = 100 cos^2 T
x^2 + y^2 = 100 [ x^2/(x^2+y^2) ]

(x^2 + y^2)^2 =100 x^2

x^4 + 2 x^2 y^2 + y^4 = 100 x^2

• Precalculus -

Thank you so much!

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