document.write( "Question 814446: if cos A = 3/5 and angle A is acute find sin 1/2 A \n" ); document.write( "
Algebra.Com's Answer #490370 by lwsshak3(11628)\"\" \"About 
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if cos A = 3/5 and angle A is acute find sin 1/2 A
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\n" ); document.write( "sinA=√(1-cos^2A)=√(1-9/25)=√(16/25)=4/5
\n" ); document.write( "sin(A/2)=√((1-cosA)/2)=√((1-(3/5))/2)=√((2/5)/2)=√(2/10)=√(1/5)=1/√5=√5/5
\n" ); document.write( "Calculator check:
\n" ); document.write( "sinA=4/5
\n" ); document.write( "A≈53.13˚
\n" ); document.write( "A/2≈26.56˚
\n" ); document.write( "sin(A/2)≈sin(26.56)≈0.447..
\n" ); document.write( "Exact value as computed=√5/5≈0.447.. \n" ); document.write( "
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