Roman C. answered 07/18/16
Tutor
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Masters of Education Graduate with Mathematics Expertise
Recall that the conversion is x = r cos θ and y = r sin θ. Also useful is x2 + y2 = r2.
1. x=2
r cos θ= 2
r cos θ= 2
r = 2 sec θ
2.2x-3y=5
2r cos θ - 3r sin θ = 5
2r cos θ - 3r sin θ = 5
r = 5/(2 cos θ - 3 sin θ)
3. x2+y2=10
r2 = 10
r2 = 10
r = √10
4. x^2-y^2=4
r2 cos2 θ - r2 sin2 θ = 4
r2 cos2 θ - r2 sin2 θ = 4
r2 cos 2θ = 4
r = 2√(sec 2θ)
5. x2+(y-1)2=1
x2 + y2 - 2y = 0
r2 = 2r sin θ
r = 2sin θ