document.write( "Question 468905: Convert the polar equation to rectangular form:\r
\n" ); document.write( "\n" ); document.write( "r=-2sin(theta)\r
\n" ); document.write( "\n" ); document.write( "Thanks!!
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Algebra.Com's Answer #321832 by ccs2011(207)\"\" \"About 
You can put this solution on YOUR website!
Use the following relationships:
\n" ); document.write( "\"x+=+r%2Acos%28theta%29\"
\n" ); document.write( "\"y+=+r%2Asin%28theta%29\"
\n" ); document.write( "\"r+=+sqrt%28x%5E2+%2B+y%5E2%29\"
\n" ); document.write( "Now substitute into given equation:
\n" ); document.write( "\"r+=+-2%2Asin%28theta%29\"
\n" ); document.write( "Notice we can solve for sin(theta)
\n" ); document.write( "\"sin%28theta%29+=+y%2Fr+=+y%2Fsqrt%28x%5E2+%2B+y%5E2%29\"
\n" ); document.write( "Thus equation becomes
\n" ); document.write( "\"sqrt%28x%5E2+%2B+y%5E2%29+=+-2%2A%28y%2Fsqrt%28x%5E2+%2B+y%5E2%29%29\"
\n" ); document.write( "Multiply by sqrt(x^2 + y^2) on both sides
\n" ); document.write( "\"x%5E2+%2B+y%5E2+=+-2y\"
\n" ); document.write( "Add 2y to both sides
\n" ); document.write( "\"x%5E2+%2B+y%5E2+%2B2y+=+0\"
\n" ); document.write( "Use completing the square to obtain standard circle equation
\n" ); document.write( "\"x%5E2+%2B+y%5E2+%2B+2y+%2B1+=+1\"
\n" ); document.write( "\"x%5E2+%2B+%28y%2B1%29%5E2+=+1\"
\n" ); document.write( "Therefore polar equation is converted to rectangular form and is the graph of a circle of radius 1 centered at (0,-1).
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