document.write( "Question 520169: Find sinalpha if tan(alpha/2)=1/root2 \n" ); document.write( "
Algebra.Com's Answer #345975 by stanbon(75887)\"\" \"About 
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Find sin(alpha) if tan(alpha/2) = 1/sqrt(2)
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\n" ); document.write( "Since tan(alpha/2) = y/x = 1/sqrt(2),
\n" ); document.write( "y = 1 when x = sqrt(2)
\n" ); document.write( "So, r = sqrt[1^2+(sqrt(2))^2] = sqrt(1+2) = sqrt(3)
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\n" ); document.write( "Then sin(alpha/2) = y/r = 1/sqrt(3)
\n" ); document.write( "and cos(alpha/2) = x/r = sqrt(2)/sqrt(3) = (1/3)sqrt(6)
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\n" ); document.write( "Finally, sin(alpha) = sin(2(alpha/2)) = 2sin(alpha/2)*cos(alpha/2)
\n" ); document.write( "= 2
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\n" ); document.write( "= (2sqrt(6)/(3*sqrt(3))
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\n" ); document.write( "= (2/3)[sqrt(18)/3]
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\n" ); document.write( "= (2/3)sqrt(2)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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