document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=852241>Question 852241</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given that angle X is in the first quadrant and cosX = 15/17 and angle Y terminates in the second quadrant (pi/2 < Y < pi) and sin Y = 12/13, then find the value of cos(Y-X) in fraction form. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #513264 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=513264\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given that angle X is in the first quadrant and <BR>\n" );
document.write( "cosX = 15/17<BR>\n" );
document.write( "sin(X) = sqrt(17^2-15^2)/17 = 8/17<BR>\n" );
document.write( "------------------------------------------------------<BR>\n" );
document.write( " and angle Y terminates in the second quadrant (pi/2 < Y < pi) and <BR>\n" );
document.write( "sin Y = 12/13<BR>\n" );
document.write( "cos(Y) = -sqrt(13^2-12^2)/13 = -5/13<BR>\n" );
document.write( "------------------------------------------------, <BR>\n" );
document.write( "then find the value of cos(Y-X) in fraction form.<BR>\n" );
document.write( "------<BR>\n" );
document.write( "cos(y-x) = cos(y)cos(x)+sin(y)sin(x) <BR>\n" );
document.write( "= (-5/13)(15/17)+(12/13)(8/17)<BR>\n" );
document.write( "= (-75+96)/(13*17)<BR>\n" );
document.write( "= (21)/(13*17)<BR>\n" );
document.write( "====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );