document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=923335>Question 923335</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Prove that:<BR>\n" );
document.write( "TanA - CotA = -2Cot2A<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 #559962 by </B><A HREF=/tutors/aboutme.mpl?userid=ewatrrr><B>ewatrrr(24785)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ewatrrr><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=ewatrrr><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=559962\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  -2Cot2A = -2(1-Tan^2A)/2TanA) = (Tan^2A-1)/TanA = TanA - 1/TanA = TanA - CotA  </SPAN>\n" );
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