document.write( "Question 1011263: Please solve this: Use the sum and difference identities to prove that:\r
\n" ); document.write( "\n" ); document.write( "sin(x+y)-sin(x-y) = 2cosxsiny \n" ); document.write( "
Algebra.Com's Answer #626886 by MathLover1(20850)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "prove that:
\n" ); document.write( "\"sin%28x%2By%29-sin%28x-y%29+=+2cos%28x%29sin%28y%29+\"\r
\n" ); document.write( "\n" ); document.write( "by definition\r
\n" ); document.write( "\n" ); document.write( "\"sin+%28x+%2B+y%29++=+sin+%28x%29+cos%28y%29+%2B+cos+%28x%29+sin+%28y%29\"
\n" ); document.write( "\"sin+%28x+-y%29++=+sin+%28x%29+cos+%28y%29+-cos+%28x%29+sin%28y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"sin%28x%2By%29-sin%28x-y%29+=+cos+%28x%29+sin+%28y%29%2Bcos+%28x%29+sin%28y%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"sin%28x%2By%29-sin%28x-y%29+=+2cos+%28x%29+sin+%28y%29\"\r
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