document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=809692>Question 809692</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Cos x - 2sin^2x=1 find all real numbers that satisfy the equation<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #487725 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=487725\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Cos x - 2sin^2x=1 find all real numbers that satisfy the equation<BR>\n" );
document.write( "Cos x - 2sin^2x = 1<BR>\n" );
document.write( "cos(x) - 2(1-cos^2(x)) = 1<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "cos(x) - 2 + 2cos^2(x) = 1<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "Rearrange:<BR>\n" );
document.write( "2cos^2(x) + cos(x) - 3 = 0<BR>\n" );
document.write( "====<BR>\n" );
document.write( "Factor::<BR>\n" );
document.write( "(2cos(x) +3)((cos(x)-1) = 0<BR>\n" );
document.write( "============<BR>\n" );
document.write( "cos(x) = -3/2 or cos(x) = 1<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Note:: cos(x)= -3/2 is extraneous.<BR>\n" );
document.write( "------<BR>\n" );
document.write( "x = 0 <BR>\n" );
document.write( "================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "================<BR>\n" );
document.write( " <BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );