document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1072510>Question 1072510</A>: <I><SPAN STYLE=\"word-break: break-all;\"> prove the following identity\r<BR>\n" );
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document.write( "1. cos^2 3x - cos6x = sin^2 3x\r<BR>\n" );
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document.write( "find the general solution of:\r<BR>\n" );
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document.write( "2cos^2 x + cos2x + sin2x =0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #687469 by </B><A HREF=/tutors/aboutme.mpl?userid=ikleyn><B>ikleyn(52788)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ikleyn><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=ikleyn><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=687469\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .<BR>\n" );
document.write( "prove the following identity\r<BR>\n" );
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document.write( "1. cos^2 3x - cos6x = sin^2 3x<BR>\n" );
document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~\r<BR>\n" );
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document.write( "Apply the formula cos(2a) = cos^2(a) - sin^2(a).\r\n" );
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document.write( "Take a = 3x. You will get\r\n" );
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document.write( "cos(6x) = cos^2(3x) - sin^2(3x), \r\n" );
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document.write( "which is what has to be proved.\r\n" );
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document.write( " </SPAN>\n" );
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