document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=427300>Question 427300</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need to prove that<BR>\n" );
document.write( "(2sinx+3cosx)^2 + (3sinx-2cosx)^2 = 13<BR>\n" );
document.write( "work would be appreciated. thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #297191 by </B><A HREF=/tutors/aboutme.mpl?userid=richard1234><B>richard1234(7193)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richard1234><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/cgi-bin/show-face.mpl?user=richard1234><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=297191\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Expand the left side:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%284sin%5E2%28x%29+%2B+12sin%28x%29cos%28x%29+%2B+9+cos%5E2%28x%29%29+%2B+%289sin%5E2%28x%29+-+12sin%28x%29cos%28x%29+%2B+4cos%5E2%28x%29%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "The <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12+sin%28x%29cos%28x%29 ALIGN=MIDDLE  ALT=\"12+sin%28x%29cos%28x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > terms cancel out, leaving\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4sin%5E2%28x%29+%2B+9+cos%5E2%28x%29+%2B+9sin%5E2%28x%29+%2B+4cos%5E2%28x%29 ALIGN=MIDDLE  ALT=\"4sin%5E2%28x%29+%2B+9+cos%5E2%28x%29+%2B+9sin%5E2%28x%29+%2B+4cos%5E2%28x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Collect like terms to obtain\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=13sin%5E2%28x%29+%2B+13cos%5E2%28x%29+=+13%28sin%5E2%28x%29+%2B+cos%5E2%28x%29%29 ALIGN=MIDDLE  ALT=\"13sin%5E2%28x%29+%2B+13cos%5E2%28x%29+=+13%28sin%5E2%28x%29+%2B+cos%5E2%28x%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >. Since <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%5E2%28x%29+%2B+cos%5E2%28x%29+=+1 ALIGN=MIDDLE  ALT=\"sin%5E2%28x%29+%2B+cos%5E2%28x%29+=+1\"   DISABLED_style= \"max-width:90%; height:auto;\" > we conclude that the entire expression is equal to 13. </SPAN>\n" );
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