document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=689562>Question 689562</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help on trig identities. <BR>\n" );
document.write( "Verify the following equation:<BR>\n" );
document.write( "cosx(cosx-secx)=-sin^2x<BR>\n" );
document.write( "So far I used the foil method to get cos^2x-cosxsecx but I'm not sure if that is right </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #426063 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=426063\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Verify the following equation:<BR>\n" );
document.write( "cosx(cosx-secx)=-sin^2x<BR>\n" );
document.write( "start with left side<BR>\n" );
document.write( "cosx(cosx-secx)<BR>\n" );
document.write( "=cosx(cosx-1/cosx)<BR>\n" );
document.write( "=cos^2x-1<BR>\n" );
document.write( "=-(1-cos^2x)<BR>\n" );
document.write( "=-sin^2x<BR>\n" );
document.write( "verified:<BR>\n" );
document.write( "left side=right side </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );