document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=505227>Question 505227</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Decide whether the equation is a trigonometric identiye explain your reasoning.<BR>\n" );
document.write( "cos^2x(1+tan^2x)=1<BR>\n" );
document.write( "secxtanx(1-sin^2x)=sinx<BR>\n" );
document.write( "cos^2(2x)-sin^2=0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #339863 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=339863\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Decide whether the equation is a trigonometric identity explain your reasoning.<BR>\n" );
document.write( "cos^2x(1+tan^2x)=1<BR>\n" );
document.write( "secxtanx(1-sin^2x)=sinx<BR>\n" );
document.write( "cos^2(2x)-sin^2=0<BR>\n" );
document.write( "**<BR>\n" );
document.write( "cos^2x(1+tan^2x)=1<BR>\n" );
document.write( "cos^2x+sin^2x/cos^2x=1<BR>\n" );
document.write( "cos^2x+sin^2x=1<BR>\n" );
document.write( "left side = right side, therefore, equation is an identity<BR>\n" );
document.write( "..<BR>\n" );
document.write( "secxtanx(1-sin^2x)=sinx<BR>\n" );
document.write( "(1/cosx*sinx/cosx)(1-1+cos^2x<BR>\n" );
document.write( "(sinx/cos^2x)(cos^2x)=sinx<BR>\n" );
document.write( "left side = right side, therefore, equation is an identity<BR>\n" );
document.write( "..<BR>\n" );
document.write( "cos^2(2x)-sin^2=0<BR>\n" );
document.write( "cos^2x-sin^2x-sin^2x<BR>\n" );
document.write( "cos^2x-2sin^2x<BR>\n" );
document.write( "cos^2x-2+2cos^2x<BR>\n" );
document.write( "3cos^2x-2&#8800;0<BR>\n" );
document.write( "left side &#8800; right side, therefore, equation is not an identity </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );