document.write( "Question 958073: how to find all points when r = 3sin(theta) and r = 3 cos (2 theta) intersect \n" ); document.write( "

Algebra.Com's Answer #585611 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"sin%28theta%29=cos%282%2Atheta%29\"$
\n" ); document.write( " $\"sin%28theta%29=1-2sin%5E2%28theta%29\"$
\n" ); document.write( "Let $\"u=sin%28theta%29\"$ ,
\n" ); document.write( " $\"u=1-2u%5E2\"$
\n" ); document.write( " $\"2u%5E2%2Bu-1=0\"$
\n" ); document.write( " $\"%28u%2B1%29%282u-1%29=0\"$
\n" ); document.write( "Two solutions:
\n" ); document.write( " $\"u%2B1=0\"$
\n" ); document.write( " $\"u=-1\"$
\n" ); document.write( " $\"sin%28theta%29=-1\"$
\n" ); document.write( " $\"theta=270\"$
\n" ); document.write( "and
\n" ); document.write( " $\"2u-1=0\"$
\n" ); document.write( " $\"2u=1\"$
\n" ); document.write( " $\"u=1%2F2\"$
\n" ); document.write( " $\"sin%28theta%29=1%2F2\"$
\n" ); document.write( " $\"theta=30\"$ and $\"theta=150\"$ \r
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