document.write( "Question 1021847: For 2x^2 + xy + 2y^2 = 1, find theta, the angle of rotation about the origin, to the nearest degree \n" ); document.write( "

Algebra.Com's Answer #637750 by Fombitz(32388) $\"\"$ $\"About$

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You can find the rotation angle of the general ellipse equation,
\n" ); document.write( " $\"Ax%5E2%2B2Bxy%2BCy%5E2%2BD=0\"$
\n" ); document.write( "using,
\n" ); document.write( " $\"tan%282%2Atheta%29=%282B%29%2F%28A-C%29\"$
\n" ); document.write( "So in this case,
\n" ); document.write( " $\"tan%282%2Atheta%29=%281%29%2F%282-2%29=1%2F0\"$
\n" ); document.write( " $\"2%2Atheta=0+%2B-+90\"$
\n" ); document.write( " $\"theta=0+%2B-+45\"$
\n" ); document.write( "Let's graph it to see which it is.
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\n" ); document.write( ".\r
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\n" ); document.write( " $\"theta=-45\"$ \n" ); document.write( "

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