document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=437816>Question 437816</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can you please solve this equation and find all solutions? And give an explanation?\r<BR>\n" );
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document.write( "I am not sure whether to write it like this:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4cos%282x%29%5E2+-+1+=+0+ ALIGN=MIDDLE  ALT=\"+4cos%282x%29%5E2+-+1+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "or like this:\r<BR>\n" );
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document.write( "4cos^2(2x) - 1 = 0\r<BR>\n" );
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document.write( "Thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #302889 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=302889\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The 2 ways to write it shown make it 2 different problems.<BR>\n" );
document.write( "If it's cosine squared, it's<BR>\n" );
document.write( "4cos^2(2x) - 1 = 0<BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "cos^2(2x) = 1/4<BR>\n" );
document.write( "cos(2x) = ± 1/2<BR>\n" );
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document.write( "cos(2x) = +1/2<BR>\n" );
document.write( "2x = 60 degs + n*360, n = 0,1,2,3...<BR>\n" );
document.write( "x = 30 degs + n*180, n = 0,1,2,3...<BR>\n" );
document.write( "2x = 300 degs + n*360, n = 0,1,2,3...<BR>\n" );
document.write( "x = 150 degs + n*180, n = 0,1,2,3...<BR>\n" );
document.write( "---------------<BR>\n" );
document.write( "cos(2x) = -1/2<BR>\n" );
document.write( "2x = 120 degs + n*360, n = 0,1,2,3...<BR>\n" );
document.write( "x = 60 + n*180, n = 0,1,2,3...<BR>\n" );
document.write( "-------<BR>\n" );
document.write( "2x = 240 degs + n*360, n = 0,1,2,3...<BR>\n" );
document.write( "x = 120 + n*180, n = 0,1,2,3...<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );