document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=921419>Question 921419</A>: <I><SPAN STYLE=\"word-break: break-all;\"> prove that :<BR>\n" );
document.write( "2 (cos^2)A+ cos A - 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 #558986 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=558986\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 2 cos^2(A)+ cos(A) - 1 = 0<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "Factor:<BR>\n" );
document.write( "(2cos(A)-1)(cos(A)+1) = 0<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "cos(A) = 1/2 or cos(A) = -1<BR>\n" );
document.write( "----<BR>\n" );
document.write( "A = +/- 60 degrees OR A = 180 degrees<BR>\n" );
document.write( "---------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );