document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=138472>Question 138472</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0534380298/algebrahomeworkh>Algebra and Trigonometry</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Hi, the problem cos^2 2x - sin^2 2x=0 is giving me trouble.  I don't know what to do to solve it.  Please help me.  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 #101109 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=101109\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> cos^2 2x - sin^2 2x=0 \r<BR>\n" );
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document.write( "----------------------------<BR>\n" );
document.write( "cos^2(2x) - [ 1-cos^2(2x)] = 0<BR>\n" );
document.write( "2cos^2(2x) = 1<BR>\n" );
document.write( "cos^2(2x) = 1/2<BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "cos(2x) = sqrt(2)/2<BR>\n" );
document.write( "2x = 45 degrees or -45 degrees<BR>\n" );
document.write( "x = 22.5 degrees or -22.5 degrees\r<BR>\n" );
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document.write( "====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );