document.write( "Question 702688: 1. If sin x=1/√5,and cos x is less than 0, find sin 2x.
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Algebra.Com's Answer #433114 by sachi(548) $\"\"$ $\"About$

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If sin x=1/√5,
\n" ); document.write( "and cos x =sqrt(1-sin^2x)=sqrt(1-1/5)=+/- 2/√5 is less than 0
\n" ); document.write( "so cos x =- 2/√5
\n" ); document.write( " sin 2x=2 sinx cosx=2*1/√5*2/√5=2/5
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