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" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #559969 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=559969\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Prove that:<BR>\n" );
document.write( "TanA - CotA = -2Cot2A<BR>\n" );
document.write( "***<BR>\n" );
document.write( "use x for A<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=tanx-cotx=-2cot%5E2%28x%29 ALIGN=MIDDLE  ALT=\"tanx-cotx=-2cot%5E2%28x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "start with left side:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=tanx-cotx=sinx%2Fcosx-cosx%2Fsinx%0D%0A=%28sin%5E2%28x%29-cos%5E2%28x%29%29%2Fsinxcosx%0D%0A=-%28%28cos%5E2%28x%29-sin%5E2%28x%29%29%29%2Fsinxcosx=-cos%282x%29%2Fsinxcosx%0D%0A=-2%2Acos%282x%29%2F%282%2Asinxcosx%29=-2cos%282x%29%2F%28sin%282x%29%29=-cot%282x%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "verified: left side=right side </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );