document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=836084>Question 836084</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Sorry, but I don't understand how to do these sort of questions...<BR>\n" );
document.write( "Prove the following identities<BR>\n" );
document.write( "2tan^2/1+tan^2 =2 sin^2<BR>\n" );
document.write( "Sin^2(1+sec^2)=sec^2-cos^2<BR>\n" );
document.write( "1-sinA+cosA/1-sinA= 1+sinA+cosA/cosA\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Please help, Thank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #503996 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=503996\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Prove the following identities<BR>\n" );
document.write( "2tan^2/1+tan^2 =2 sin^2<BR>\n" );
document.write( "Note: 1+tan^2 = sec^2<BR>\n" );
document.write( "----<BR>\n" );
document.write( "So, 2tan^2/sec^2 = 2sin^2<BR>\n" );
document.write( "Then 2[sin^2/cos^2]/[1/cos^2] = 2sin^2<BR>\n" );
document.write( "Therefore: 2[sin^2/cos^2] = 2sin^2<BR>\n" );
document.write( "Finally: 2sin^2 = 2sin^2\r<BR>\n" );
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document.write( "--------------------\r<BR>\n" );
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document.write( "Sin^2(1+sec^2)=sec^2-cos^2<BR>\n" );
document.write( "---------<BR>\n" );
document.write( "Multiply on the left side:<BR>\n" );
document.write( "Convert sec^2 to tan^2+1 on the right side<BR>\n" );
document.write( "sin^2 + tan^2 = tan^2+1 - cos^2<BR>\n" );
document.write( "------<BR>\n" );
document.write( "Rearrange the right side:<BR>\n" );
document.write( "sin^2 + tan^2 = tan^2 + [1-cos^2]<BR>\n" );
document.write( "------<BR>\n" );
document.write( "Apply: sin^2 = 1-cos^2 to get<BR>\n" );
document.write( "sin^2 + tan^2 = tan^2 + sin^2<BR>\n" );
document.write( "========================================\r<BR>\n" );
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document.write( "1-sinA+cosA/1-sinA= 1+sinA+cosA/cosA<BR>\n" );
document.write( "Comment: This is confusing.<BR>\n" );
document.write( "Using parentheses, show where numerators and denominators begin and end.<BR>\n" );
document.write( "==================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan <BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );