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$xy=7$

we get:

$r(\cos(\theta)\sin(\theta))=7$

therefore the only logical equation that could possibly arise is:

$r=\frac{7}{\cos(\theta)\sin(\theta)}$

yet web assign said nope $#%& off. Am I missing something basic here or is web assign dead wrong?

JDF
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K. Gibson
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    If $x = r \cos \theta$ and $y = r \sin \theta$, then $x y = r \cos \theta \cdot r \sin \theta = r^2 \cos \theta \sin \theta$. – Luca Bressan Sep 09 '16 at 19:05

1 Answers1

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$$xy=r\cos\theta r\sin \theta$$ $$r^2=\frac{7}{\cos(\theta)\sin(\theta)}$$ $$r^2=\frac{7}{\sin(2\theta)/2}$$ $$r^2=14\csc 2\theta$$

E.H.E
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