document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=843806>Question 843806</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the solutions of the equation that are in the interval [0, 2pi).\r<BR>\n" );
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document.write( "cos u + cos 2u = 0  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #508391 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=508391\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the solutions of the equation that are in the interval [0, 2pi).<BR>\n" );
document.write( "cos u + cos 2u = 0 <BR>\n" );
document.write( "cosu+cos^2u-sin^2u=0<BR>\n" );
document.write( "cosu+cos^2u-(1-cos^2u)=0<BR>\n" );
document.write( "cosu+cos^2u-1+cos^2u=0<BR>\n" );
document.write( "2cos^2u+cosu-1=0<BR>\n" );
document.write( "(2cosu-1)(cosu+1)=0<BR>\n" );
document.write( "cosu=1/2<BR>\n" );
document.write( "u=&#960;/3,5&#960;/3<BR>\n" );
document.write( "or<BR>\n" );
document.write( "cosu=-1<BR>\n" );
document.write( "u=&#960;<BR>\n" );
document.write( "solutions: &#960;/3, 5&#960;/3, &#960; </SPAN>\n" );
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