document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=573724>Question 573724</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please show me the method to prove identity here\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=++%281-secx%29%2F%281%2Bsecx%29+=+%28cosx-1%29%2F%28cosx%2B1%29++ ALIGN=MIDDLE  ALT=\"++%281-secx%29%2F%281%2Bsecx%29+=+%28cosx-1%29%2F%28cosx%2B1%29++\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #368909 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=368909\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Cross-multiply\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE (1+\sec x)(\cos x - 1) = (1-\sec x)(\cos x+1)\">\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos x - 1 + \sec x \cos x - \sec x = \cos x + 1 - \sec x \cos x - \sec x\">\r<BR>\n" );
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document.write( "Note that sec x cos x = 1. Replacing this, we have\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos x - 1 + 1 - \sec x = \cos x + 1 - 1 - \sec x\">\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=\"/cgi-bin/rendertex.cgi?\LARGE \cos x - \sec x = \cos x - \sec x\">\r<BR>\n" );
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document.write( "This is true for all x (such that sec x is defined) so the original equation is also true. </SPAN>\n" );
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