document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=906637>Question 906637</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find all solutions to the equation.\r<BR>\n" );
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document.write( "cos2x + 2 cos x + 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 #550016 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=550016\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find all solutions to the equation. <BR>\n" );
document.write( "cos2x + 2 cos x + 1 = 0<BR>\n" );
document.write( "(2cos^2-1) + 2cos + 1 = 0<BR>\n" );
document.write( "2cos^2 + 2cos = 0<BR>\n" );
document.write( "(cos)(2cos+2) = 0<BR>\n" );
document.write( "cos(x) = 0 or cos(x) = -1<BR>\n" );
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document.write( "x = pi/2 or (3/2)pi or x = pi<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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