document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=439333>Question 439333</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need help with solving cos^2x - cos2x = 0 on the interval {0,2&#960;).\r<BR>\n" );
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document.write( "(cos^2x = cos(squared)x)\r<BR>\n" );
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document.write( "This is what I have tried: <BR>\n" );
document.write( "(1)<BR>\n" );
document.write( "cos^2x - 2cos^2x - 1 = 0 (From the double-angle identity for cos2x)\r<BR>\n" );
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document.write( "cos^2x - 2cos^2x = 1<BR>\n" );
document.write( "-cos^2x = 1\r<BR>\n" );
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document.write( "Is there anything else that I could have done? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #303575 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=303575\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> I need help with solving <BR>\n" );
document.write( "cos^2x - cos2x = 0 on the interval {0,2&#960;).<BR>\n" );
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document.write( "Note: cos(2x) = 2cos^2(x)-1<BR>\n" );
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document.write( "cos^2(x)-[2cos^2(x)-1] = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "-cos^2(x)+1 = 0<BR>\n" );
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document.write( "cos^2(x) - 1 = 0<BR>\n" );
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document.write( "Factor:<BR>\n" );
document.write( "(cos(x)-1)(cos(x)+1) = 0<BR>\n" );
document.write( "cos(x) = 1 or cos(x) = -1<BR>\n" );
document.write( "x = 0 or x = pi<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "============== <BR>\n" );
document.write( " </SPAN>\n" );
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