How do I convert this equation to polar coordinates?












0














Convert the equation $(x^2 + y^2)^2 = 2xy$ into polar coordinates.



I tried converting the equation in the image to polar coordinates and got $r= sqrt{sin(2theta)}$.



This answer is wrong, but I do not understand why. Can someone please explain what the correct answer is?










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  • What is the answer given?
    – Akash Roy
    Nov 23 at 5:14










  • The answer was not provided.
    – VRM
    Nov 23 at 5:15










  • You probably need both the positive and negative square roots.
    – John Douma
    Nov 23 at 5:16










  • Yeah that could be the only possibility.
    – Akash Roy
    Nov 23 at 5:17










  • There is not an option for that.
    – VRM
    Nov 23 at 5:17
















0














Convert the equation $(x^2 + y^2)^2 = 2xy$ into polar coordinates.



I tried converting the equation in the image to polar coordinates and got $r= sqrt{sin(2theta)}$.



This answer is wrong, but I do not understand why. Can someone please explain what the correct answer is?










share|cite|improve this question
























  • What is the answer given?
    – Akash Roy
    Nov 23 at 5:14










  • The answer was not provided.
    – VRM
    Nov 23 at 5:15










  • You probably need both the positive and negative square roots.
    – John Douma
    Nov 23 at 5:16










  • Yeah that could be the only possibility.
    – Akash Roy
    Nov 23 at 5:17










  • There is not an option for that.
    – VRM
    Nov 23 at 5:17














0












0








0


1





Convert the equation $(x^2 + y^2)^2 = 2xy$ into polar coordinates.



I tried converting the equation in the image to polar coordinates and got $r= sqrt{sin(2theta)}$.



This answer is wrong, but I do not understand why. Can someone please explain what the correct answer is?










share|cite|improve this question















Convert the equation $(x^2 + y^2)^2 = 2xy$ into polar coordinates.



I tried converting the equation in the image to polar coordinates and got $r= sqrt{sin(2theta)}$.



This answer is wrong, but I do not understand why. Can someone please explain what the correct answer is?







trigonometry






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Nov 24 at 2:48









N. F. Taussig

43.5k93355




43.5k93355










asked Nov 23 at 5:09









VRM

1




1












  • What is the answer given?
    – Akash Roy
    Nov 23 at 5:14










  • The answer was not provided.
    – VRM
    Nov 23 at 5:15










  • You probably need both the positive and negative square roots.
    – John Douma
    Nov 23 at 5:16










  • Yeah that could be the only possibility.
    – Akash Roy
    Nov 23 at 5:17










  • There is not an option for that.
    – VRM
    Nov 23 at 5:17


















  • What is the answer given?
    – Akash Roy
    Nov 23 at 5:14










  • The answer was not provided.
    – VRM
    Nov 23 at 5:15










  • You probably need both the positive and negative square roots.
    – John Douma
    Nov 23 at 5:16










  • Yeah that could be the only possibility.
    – Akash Roy
    Nov 23 at 5:17










  • There is not an option for that.
    – VRM
    Nov 23 at 5:17
















What is the answer given?
– Akash Roy
Nov 23 at 5:14




What is the answer given?
– Akash Roy
Nov 23 at 5:14












The answer was not provided.
– VRM
Nov 23 at 5:15




The answer was not provided.
– VRM
Nov 23 at 5:15












You probably need both the positive and negative square roots.
– John Douma
Nov 23 at 5:16




You probably need both the positive and negative square roots.
– John Douma
Nov 23 at 5:16












Yeah that could be the only possibility.
– Akash Roy
Nov 23 at 5:17




Yeah that could be the only possibility.
– Akash Roy
Nov 23 at 5:17












There is not an option for that.
– VRM
Nov 23 at 5:17




There is not an option for that.
– VRM
Nov 23 at 5:17










1 Answer
1






active

oldest

votes


















0














Did you get something similar to this?



For the original equation $$(x^2 + y^2)^2 = 2 x y$$



Let $$begin {matrix} x = r cos theta \ y = r sin theta \ r^2 = x^2 + y^2 end {matrix}$$



Plugging all of this in to the original equation we get



$$(r^2)^2 = 2r^2 sin theta cos theta$$



or



$$r^4 = 2 r^2 sin theta cos theta$$



Dividing by $r^2$ we have



$$r^2 = 2 sin theta cos theta$$



However, $2 sin theta cos theta = sin 2 theta$ so we end up with



$$r^2 = sin 2 theta$$



We can leave as-is (I think this may be the answer they're expecting) or take square roots...



$$r = pm sqrt {sin 2 theta}$$






share|cite|improve this answer























  • I think it's supposed to be square root of sine double angle.
    – VRM
    Nov 24 at 2:04










  • Thanks, VRM - my mistake! Fixed.
    – bjcolby15
    Nov 24 at 2:43













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1 Answer
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active

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1 Answer
1






active

oldest

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active

oldest

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active

oldest

votes









0














Did you get something similar to this?



For the original equation $$(x^2 + y^2)^2 = 2 x y$$



Let $$begin {matrix} x = r cos theta \ y = r sin theta \ r^2 = x^2 + y^2 end {matrix}$$



Plugging all of this in to the original equation we get



$$(r^2)^2 = 2r^2 sin theta cos theta$$



or



$$r^4 = 2 r^2 sin theta cos theta$$



Dividing by $r^2$ we have



$$r^2 = 2 sin theta cos theta$$



However, $2 sin theta cos theta = sin 2 theta$ so we end up with



$$r^2 = sin 2 theta$$



We can leave as-is (I think this may be the answer they're expecting) or take square roots...



$$r = pm sqrt {sin 2 theta}$$






share|cite|improve this answer























  • I think it's supposed to be square root of sine double angle.
    – VRM
    Nov 24 at 2:04










  • Thanks, VRM - my mistake! Fixed.
    – bjcolby15
    Nov 24 at 2:43


















0














Did you get something similar to this?



For the original equation $$(x^2 + y^2)^2 = 2 x y$$



Let $$begin {matrix} x = r cos theta \ y = r sin theta \ r^2 = x^2 + y^2 end {matrix}$$



Plugging all of this in to the original equation we get



$$(r^2)^2 = 2r^2 sin theta cos theta$$



or



$$r^4 = 2 r^2 sin theta cos theta$$



Dividing by $r^2$ we have



$$r^2 = 2 sin theta cos theta$$



However, $2 sin theta cos theta = sin 2 theta$ so we end up with



$$r^2 = sin 2 theta$$



We can leave as-is (I think this may be the answer they're expecting) or take square roots...



$$r = pm sqrt {sin 2 theta}$$






share|cite|improve this answer























  • I think it's supposed to be square root of sine double angle.
    – VRM
    Nov 24 at 2:04










  • Thanks, VRM - my mistake! Fixed.
    – bjcolby15
    Nov 24 at 2:43
















0












0








0






Did you get something similar to this?



For the original equation $$(x^2 + y^2)^2 = 2 x y$$



Let $$begin {matrix} x = r cos theta \ y = r sin theta \ r^2 = x^2 + y^2 end {matrix}$$



Plugging all of this in to the original equation we get



$$(r^2)^2 = 2r^2 sin theta cos theta$$



or



$$r^4 = 2 r^2 sin theta cos theta$$



Dividing by $r^2$ we have



$$r^2 = 2 sin theta cos theta$$



However, $2 sin theta cos theta = sin 2 theta$ so we end up with



$$r^2 = sin 2 theta$$



We can leave as-is (I think this may be the answer they're expecting) or take square roots...



$$r = pm sqrt {sin 2 theta}$$






share|cite|improve this answer














Did you get something similar to this?



For the original equation $$(x^2 + y^2)^2 = 2 x y$$



Let $$begin {matrix} x = r cos theta \ y = r sin theta \ r^2 = x^2 + y^2 end {matrix}$$



Plugging all of this in to the original equation we get



$$(r^2)^2 = 2r^2 sin theta cos theta$$



or



$$r^4 = 2 r^2 sin theta cos theta$$



Dividing by $r^2$ we have



$$r^2 = 2 sin theta cos theta$$



However, $2 sin theta cos theta = sin 2 theta$ so we end up with



$$r^2 = sin 2 theta$$



We can leave as-is (I think this may be the answer they're expecting) or take square roots...



$$r = pm sqrt {sin 2 theta}$$







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Nov 24 at 2:43

























answered Nov 23 at 17:35









bjcolby15

1,1581916




1,1581916












  • I think it's supposed to be square root of sine double angle.
    – VRM
    Nov 24 at 2:04










  • Thanks, VRM - my mistake! Fixed.
    – bjcolby15
    Nov 24 at 2:43




















  • I think it's supposed to be square root of sine double angle.
    – VRM
    Nov 24 at 2:04










  • Thanks, VRM - my mistake! Fixed.
    – bjcolby15
    Nov 24 at 2:43


















I think it's supposed to be square root of sine double angle.
– VRM
Nov 24 at 2:04




I think it's supposed to be square root of sine double angle.
– VRM
Nov 24 at 2:04












Thanks, VRM - my mistake! Fixed.
– bjcolby15
Nov 24 at 2:43






Thanks, VRM - my mistake! Fixed.
– bjcolby15
Nov 24 at 2:43




















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