Thread: Converting a polar equation to a rectangular equation

I was given the polar equation: r + 2cos(theta) = 3sin(theta)

Which I converted (I believe correctly) to x^2+y^2=-2x+3y yet my professor circled my answer and circled the word "Equation" in the question. I feel like what I did was right but is there another form I am supposed to put this in? Thank you.

Originally Posted by beastcoast515

I was given the polar equation: r + 2cos(theta) = 3sin(theta)

Which I converted (I believe correctly) to x^2+y^2=-2x+3y yet my professor circled my answer and circled the word "Equation" in the question. I feel like what I did was right but is there another form I am supposed to put this in? Thank you.

So this is a circle of radius units centred at .

Yes, that's obviously a circle but the question was, why did the professor circle it and write "equation"? beastcoast515, look closely at your paper again. Is it possible that you simply forgot to write "=" or that you wrote it quickly and it was not easily readable as an equality symbol?
Other than that, if you actually wrote what you say here, I can think of no good reason.

Originally Posted by HallsofIvy

Yes, that's obviously a circle but the question was, why did the professor circle it and write "equation"? beastcoast515, look closely at your paper again. Is it possible that you simply forgot to write "=" or that you wrote it quickly and it was not easily readable as an equality symbol?
Other than that, if you actually wrote what you say here, I can think of no good reason.

Or if the question asked to DESCRIBE the curve given by the equation. There's nearly always an expectation of inference from doing a question...