document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=876535>Question 876535</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given that tan theta = 15/8 with theta in quadrant I, find cos 2 theta </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #528830 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=528830\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given that tan theta = 15/8 with theta in quadrant I, find cos 2 theta<BR>\n" );
document.write( "***<BR>\n" );
document.write( "Hypotenuse of working reference right triangle in  quadrant I=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%2815%5E2%2B8%5E2%29=sqrt%28225%2B64%29=sqrt%28289%29=17 ALIGN=MIDDLE  ALT=\"sqrt%2815%5E2%2B8%5E2%29=sqrt%28225%2B64%29=sqrt%28289%29=17\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28theta%29=15%2F17 ALIGN=MIDDLE  ALT=\"sin%28theta%29=15%2F17\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28theta%29=8%2F17 ALIGN=MIDDLE  ALT=\"cos%28theta%29=8%2F17\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%282theta%29=cos%5E2%28theta%29-sin%5E2%28theta%29=64%2F289-225%2F289=-161%2F289 ALIGN=MIDDLE  ALT=\"cos%282theta%29=cos%5E2%28theta%29-sin%5E2%28theta%29=64%2F289-225%2F289=-161%2F289\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "calculator check:<BR>\n" );
document.write( "tan theta=15/8<BR>\n" );
document.write( "theta&#8776;61.9275&#730;<BR>\n" );
document.write( "2theta&#8776;123.86&#730;<BR>\n" );
document.write( "cos(2theta)&#8776;cos(123.86&#730;)&#8776;-0.5572…<BR>\n" );
document.write( "Exact value=-161/189&#8776;-0.5571…<BR>\n" );
document.write( "let me know if my answer is correct and the method used is understandable </SPAN>\n" );
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