document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=312174>Question 312174</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this question and show all steps if possible thank you!<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3+cos2x=+cosx+%2B2 ALIGN=MIDDLE  ALT=\"3+cos2x=+cosx+%2B2\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #223191 by </B><A HREF=/tutors/aboutme.mpl?userid=fractalier><B>fractalier(6550)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=fractalier><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/cgi-bin/show-face.mpl?user=fractalier><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=223191\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Okay from <BR>\n" );
document.write( "3 cos2x = cosx +2<BR>\n" );
document.write( "let's apply our identity for cos 2x...<BR>\n" );
document.write( "cos 2x = cos^2 x - sin^2 x = 2 cos^2 x - 1<BR>\n" );
document.write( "so that if we substitute we get<BR>\n" );
document.write( "3(2 cos^2 x - 1) = cos x + 2<BR>\n" );
document.write( "6 cos^2 x - 3 = cos x + 2<BR>\n" );
document.write( "6 cos^2 x - cos x - 5 = 0  now factor this...<BR>\n" );
document.write( "(6 cos x + 5)(cos x - 1) = 0<BR>\n" );
document.write( "and then<BR>\n" );
document.write( "cos x = -5/6  or  cos x = 1<BR>\n" );
document.write( "x = arc cos (-5/6)  or  x = 0 </SPAN>\n" );
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