document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=28554>Question 28554</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Gidday<BR>\n" );
document.write( "      I have been asked to prove the following identity, and i have absolutely no idea what is being asked for.\r<BR>\n" );
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document.write( "cos^2theta - sin^2theta = 1 - 2(sin^2theta)\r<BR>\n" );
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document.write( "Thanks Darryl </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #15536 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><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=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=15536\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%5E2%28A%29+-+sin%5E2%28A%29+ ALIGN=MIDDLE  ALT=\"cos%5E2%28A%29+-+sin%5E2%28A%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "now, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%5E2%28A%29+%2B+sin%5E2%28A%29+=+1+ ALIGN=MIDDLE  ALT=\"cos%5E2%28A%29+%2B+sin%5E2%28A%29+=+1+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "so that <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%5E2%28A%29+=+1+-+sin%5E2%28A%29+ ALIGN=MIDDLE  ALT=\"cos%5E2%28A%29+=+1+-+sin%5E2%28A%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "so, put that into the top equation, giving:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1+-+sin%5E2%28A%29+-+sin%5E2%28A%29+ ALIGN=MIDDLE  ALT=\"1+-+sin%5E2%28A%29+-+sin%5E2%28A%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "which becomes <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1+-+2sin%5E2%28A%29+ ALIGN=MIDDLE  ALT=\"1+-+2sin%5E2%28A%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > which is the other side of the Question... so this proves it.\r<BR>\n" );
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document.write( "jon.<BR>\n" );
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