document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=824857>Question 824857</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given that Sin A = 4/5, 0 < A <  &#960;/2 and Cos B = -12/13, &#960;< B <  3&#960;/2, find Cos (A - B)<BR>\n" );
document.write( "a.)	-56/65                          b.) 56/65                               c.) 63/65                              d.) -63/65 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #497063 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=497063\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given that Sin A = 4/5, 0 < A < &#960;/2 and Cos B = -12/13, &#960;< B < 3&#960;/2, find Cos (A - B)<BR>\n" );
document.write( "***<BR>\n" );
document.write( "Identity: cos(A-B)=cosAcosB+sinAsinB<BR>\n" );
document.write( "sinA=4/5 (working with (3-4-5) reference right triangle in quadrant I in which sin and cos>0.<BR>\n" );
document.write( "cosA=3/5<BR>\n" );
document.write( "..<BR>\n" );
document.write( "cosB=-12/13 (working with (5-12-13) reference right triangle in quadrant III in which sin and cos<0.<BR>\n" );
document.write( "sinB=-5/13<BR>\n" );
document.write( "..<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28A-B%29=%28%283%2F5%29%2A%28-12%2F13%29%29%2B%28%284%2F5%29%2A%28-5%2F13%29%29=-56%2F65 ALIGN=MIDDLE  ALT=\"cos%28A-B%29=%28%283%2F5%29%2A%28-12%2F13%29%29%2B%28%284%2F5%29%2A%28-5%2F13%29%29=-56%2F65\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "ans: a) -56/65<BR>\n" );
document.write( " </SPAN>\n" );
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