document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=744624>Question 744624</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given that sin A= -4/5 where A is in quadrant 3 and sin B= 12/13 where B is in quadrant 2. Find:\r<BR>\n" );
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document.write( "A. cosA\r<BR>\n" );
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document.write( "B. cosB\r<BR>\n" );
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document.write( "C. sec(A-B)\r<BR>\n" );
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document.write( "D. tan(2A)\r<BR>\n" );
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document.write( "E. cos(B/2)\r<BR>\n" );
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document.write( "Help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #453509 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=453509\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Given that sin A= -4/5 where A is in quadrant 3 and sin B= 12/13 where B is in quadrant 2. Find: <BR>\n" );
document.write( "A. cosA=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-sqrt%281-sin%5E2%28A%29%29=-sqrt%281-%2816%2F25%29%29=-sqrt%289%2F25%29=-3%2F5 ALIGN=MIDDLE  ALT=\"-sqrt%281-sin%5E2%28A%29%29=-sqrt%281-%2816%2F25%29%29=-sqrt%289%2F25%29=-3%2F5\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "..<BR>\n" );
document.write( "B. cosB =<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-sqrt%281-sin%5E2%28B%29%29=-sqrt%281-%28144%2F169%29%29=-sqrt%2825%2F169%29=-5%2F13 ALIGN=MIDDLE  ALT=\"-sqrt%281-sin%5E2%28B%29%29=-sqrt%281-%28144%2F169%29%29=-sqrt%2825%2F169%29=-5%2F13\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "..<BR>\n" );
document.write( "C. sec(A-B)=1/cos(A-B)<BR>\n" );
document.write( "cos(A-B)=cosA cosB+SinA sinB=-3/5*-5/13+(-4/5)*12/13=15/65-48/65=-33/65<BR>\n" );
document.write( "sec(A-B)=-65/33<BR>\n" );
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document.write( "D. tan(2A)=(2tanA)/(1-tan^2A)<BR>\n" );
document.write( "tanA=sinA/cosA=(-4/5)/(-3/5)=4/3<BR>\n" );
document.write( "tan(2A)=(8/3)/(1-16/9)=(8/3)/(-7/9)=-72/21<BR>\n" );
document.write( ".. <BR>\n" );
document.write( "E. cos(B/2)=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%28%281%2BcosB%29%2F2%29=sqrt%28%281%2B%28-5%2F13%29%29%2F2%29%29 ALIGN=MIDDLE  ALT=\"sqrt%28%281%2BcosB%29%2F2%29=sqrt%28%281%2B%28-5%2F13%29%29%2F2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >=&#8730;((8/13)/2))=&#8730;(8/26) </SPAN>\n" );
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