document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=834508>Question 834508</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find all real numbers in the interval [0, 2pi] which satisfy the following equation. Use special angles.\r<BR>\n" );
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document.write( "2cos2x+1=0 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #503043 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=503043\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find all real numbers in the interval [0, 2pi] which satisfy the following equation. Use special angles.<BR>\n" );
document.write( "2cos2x+1=0<BR>\n" );
document.write( "cos2x=-1/2<BR>\n" );
document.write( "2x=2&#960;/3,4&#960;/3 (in quadrants II and III in which cos<0)<BR>\n" );
document.write( "x=&#960;/3,2&#960;/3 </SPAN>\n" );
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