document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=595489>Question 595489</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if secx=4 what does cos2x= </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #377179 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><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=377179\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> sec(x) = 4\r<BR>\n" );
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document.write( "1/cos(x) = 4\r<BR>\n" );
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document.write( "1 = 4*cos(x)\r<BR>\n" );
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document.write( "1/4 = cos(x) \r<BR>\n" );
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document.write( "cos(x) = 1/4\r<BR>\n" );
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document.write( "-------------------------------------------------------\r<BR>\n" );
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document.write( "cos(2x)\r<BR>\n" );
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document.write( "2*(cos(x))^2 - 1\r<BR>\n" );
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document.write( "2*(1/4)^2 - 1\r<BR>\n" );
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document.write( "2*(1/16) - 1\r<BR>\n" );
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document.write( "1/8 - 1\r<BR>\n" );
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document.write( "-7/8\r<BR>\n" );
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document.write( "So if sec(x) = 4, then cos(2x) = -7/8 </SPAN>\n" );
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