How do I convert the polar equation r=10 sin thetar=10sinθ to its Cartesian equivalent?

1 Answer
Oct 2, 2014

Cartesian coordinates, also known as Rectangular coordinates, are defined in terms of xx and yy. So, for this problem thetaθ has to be eliminated/converted using basic foundations described by the unit circle and right triangle trigonometry.

r=10sin(theta)r=10sin(θ)

Remember that ...

x=r*cos(theta)x=rcos(θ)

y=r*sin(theta)y=rsin(θ)

r^2=x^2+y^2r2=x2+y2

Multiply both sides of the equation by rr

r*r=10r*sin(theta)rr=10rsin(θ)

r^2=10r*sin(theta)r2=10rsin(θ)

x^2+y^2=10r*sin(theta)x2+y2=10rsin(θ)

Use the fact that y=r*sin(theta)y=rsin(θ) to make a substitution.

x^2+y^2=10yx2+y2=10y

x^2+y^2-10y=0x2+y210y=0

The above equation is the Cartesian/Rectangular coordinate equivalent to the given Polar equation.