document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=882977>Question 882977</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If tan A=5/12 and A is in the third quadrant find <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos2A ALIGN=MIDDLE  ALT=\"cos2A\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos+%28A%2F2%29 ALIGN=MIDDLE  ALT=\"cos+%28A%2F2%29\"   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 #533351 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=533351\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If tan A=5/12 and A is in the third quadrant find <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos2A ALIGN=MIDDLE  ALT=\"cos2A\"   DISABLED_style= \"max-width:90%; height:auto;\" > and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos+%28A%2F2%29 ALIGN=MIDDLE  ALT=\"cos+%28A%2F2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "tanA=5/12 (working with a (5-12-13) reference right triangle in quadrant III in which sin<0, cos<0, tan>0<BR>\n" );
document.write( "sinA=-5/13<BR>\n" );
document.write( "cosA=-12/13<BR>\n" );
document.write( "cos 2A=cos^2A-sin^2A<BR>\n" );
document.write( "cos 2A=144/169-25/169=119/169<BR>\n" );
document.write( "..<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28A%2F2%29=sqrt%28%281%2Bcos%28A%29%29%2F2%29=sqrt%28%281-%2812%2F13%29%29%2F2%29=sqrt%28%281%2F13%29%2F2%29=sqrt%281%2F26%29=sqrt%2826%29%2F26 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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