document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=903306>Question 903306</A>: <I><SPAN STYLE=\"word-break: break-all;\"> given cot (theta) = 12/5 and 180<(theta)<270, what is cos (theta/2)? \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #548397 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=548397\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> given cot (theta) = 12/5 and 180<(theta)<270, what is cos (theta/2)?<BR>\n" );
document.write( "***<BR>\n" );
document.write( "you are working with a 5-12-13 reference right triangle in quadrant III in which cos<0<BR>\n" );
document.write( "Use x for theta<BR>\n" );
document.write( "cos x=-12/13<BR>\n" );
document.write( "cos(x/2)=-&#8730;((1+cosx)/2)=-&#8730;((1-12/13)/2)=-&#8730;((1/13)/2)=-&#8730;(1/26)=-1/&#8730;26<BR>\n" );
document.write( "Check:<BR>\n" );
document.write( "cos x=-12/13 (in Q3)<BR>\n" );
document.write( "x=202.6198&#730;<BR>\n" );
document.write( "x/2=101.3099&#730;<BR>\n" );
document.write( "cos(x/2)&#8776;cos(101.3099)&#8776;-0.1961...<BR>\n" );
document.write( "exact value as calculated=-1/&#8730;26&#8776;-0.1961... </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );