What is the polar form of x^2 + y^2 = 2xx2+y2=2x?

1 Answer
Nov 12, 2014

x^2+y^2=2xx2+y2=2x, which looks like:

enter image source here

by plugging in {(x=rcos theta),(y=rsin theta):},

=> (rcos theta)^2+(r sin theta)^2=2rcos theta

by multiplying out,

=> r^2cos^2theta+r^2sin^2theta=2rcos theta

by factoring out r^2 from the left-hand side,

=> r^2(cos^2theta+sin^2theta)=2rcos theta

by cos^2theta+sin^2theta=1,

=> r^2=2rcos theta

by dividing by r,

=> r=2cos theta, which looks like:

enter image source here

As you can see above, x^2+y^2=2x and r=2cos theta give us the same graphs.


I hope that this was helpful.