document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=359828>Question 359828</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can you help me, please? Thank you!\r<BR>\n" );
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document.write( "Prove the identity\r<BR>\n" );
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document.write( "sin(x+y) - sin(x-y) = 2cos(x)sin(y)\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #256765 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=256765\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> We're going to use the established identities\r<BR>\n" );
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document.write( "1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28A%2BB%29=sin%28A%29cos%28B%29%2Bcos%28A%29sin%28B%29 ALIGN=MIDDLE  ALT=\"sin%28A%2BB%29=sin%28A%29cos%28B%29%2Bcos%28A%29sin%28B%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28A-B%29=sin%28A%29cos%28B%29-cos%28A%29sin%28B%29 ALIGN=MIDDLE  ALT=\"sin%28A-B%29=sin%28A%29cos%28B%29-cos%28A%29sin%28B%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x%2By%29+-+sin%28x-y%29+=+2cos%28x%29sin%28y%29 ALIGN=MIDDLE  ALT=\"sin%28x%2By%29+-+sin%28x-y%29+=+2cos%28x%29sin%28y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Start with the given equation.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29+-+sin%28x-y%29+=+2cos%28x%29sin%28y%29 ALIGN=MIDDLE  ALT=\"sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29+-+sin%28x-y%29+=+2cos%28x%29sin%28y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Use the first identity (given above) to expand <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x%2By%29 ALIGN=MIDDLE  ALT=\"sin%28x%2By%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29+-+%28sin%28x%29cos%28y%29-cos%28x%29sin%28y%29%29+=+2cos%28x%29sin%28y%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > Use the second identity (given above)  to expand <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x-y%29 ALIGN=MIDDLE  ALT=\"sin%28x-y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29+-sin%28x%29cos%28y%29%2Bcos%28x%29sin%28y%29+=+2cos%28x%29sin%28y%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > Distribute.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28sin%28x%29cos%28y%29+-+sin%28x%29cos%28y%29%29%2B%28cos%28x%29sin%28y%29%2Bcos%28x%29sin%28y%29%29=+2cos%28x%29sin%28y%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > Group like terms.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0%2B2cos%28x%29sin%28y%29=2cos%28x%29sin%28y%29 ALIGN=MIDDLE  ALT=\"0%2B2cos%28x%29sin%28y%29=2cos%28x%29sin%28y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Combine like terms.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2cos%28x%29sin%28y%29=2cos%28x%29sin%28y%29 ALIGN=MIDDLE  ALT=\"2cos%28x%29sin%28y%29=2cos%28x%29sin%28y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify\r<BR>\n" );
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document.write( "So this verifies the identity.\r<BR>\n" );
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document.write( "If you need more help, email me at <a  rel=nofollow HREF=\"mailto:jim_thompson5910@hotmail.com?Subject=Algebra%20Help\">jim_thompson5910@hotmail.com</a>\r<BR>\n" );
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document.write( "Also, feel free to check out my <a  rel=nofollow HREF=\"http://www.freewebs.com/jimthompson5910/home.html\">tutoring website</a>\r<BR>\n" );
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document.write( "Jim </SPAN>\n" );
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