document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=706385>Question 706385</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Verify that each equation is an identity.\r<BR>\n" );
document.write( "\n" );
document.write( "2cos^2(theta)-1= 1-tan^2(theta)/1+tan^2(theta) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #435319 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=435319\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Verify that each equation is an identity. <BR>\n" );
document.write( "2cos^2(theta)-1= 1-tan^2(theta)/1+tan^2(theta)<BR>\n" );
document.write( "**<BR>\n" );
document.write( "Start with right side:<BR>\n" );
document.write( "1-tan^2(theta)/1+tan^2(theta)<BR>\n" );
document.write( "[1-(sin^2/cos^2)]/[1+(sin^2/cos^2)]<BR>\n" );
document.write( "[(cos^2-sin^2)/cos^2]/[(cos^2+sin^2)/cos^2]<BR>\n" );
document.write( "cos^2 cancels out and cos^2+sin^2=1<BR>\n" );
document.write( "cos^2-sin^2<BR>\n" );
document.write( "=cos^2-(1-cos^2)<BR>\n" );
document.write( "=cos^2-1+cos^2)<BR>\n" );
document.write( "=2cos^2-1<BR>\n" );
document.write( "verified: right side=left side<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );