document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=872831>Question 872831</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If cot A = 4/3, with A in Q3, Find sec 2A. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #526469 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=526469\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If cot A = 4/3, with A in Q3, Find sec 2A.<BR>\n" );
document.write( "You are working with a (3-4-5) reference right triangle in Q3 in which sin<0, cos<0<BR>\n" );
document.write( "cos A=-4/5<BR>\n" );
document.write( "sin A=-3/5<BR>\n" );
document.write( "cos 2A=cos^2A-sin^2A=16/25-9/25=7/25<BR>\n" );
document.write( "sec 2A=1/cos 2A=25/7<BR>\n" );
document.write( "..<BR>\n" );
document.write( "calculator check:<BR>\n" );
document.write( "cos A=-4/5<BR>\n" );
document.write( "A&#8776;216.87&#730;<BR>\n" );
document.write( "2A&#8776;433.74<BR>\n" );
document.write( "cos 2A&#8776;cos(433.74)&#8776;0.2799…<BR>\n" );
document.write( "Exact value=7/25&#8776;0.28<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );