document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=923637>Question 923637</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose sin x = 1/7<BR>\n" );
document.write( "cos x > 0, sin y = &#8722;2/5<BR>\n" );
document.write( "and cos y < 0. Then <BR>\n" );
document.write( "cos x = <BR>\n" );
document.write( "cos y = <BR>\n" );
document.write( "Find each of the following quantities: <BR>\n" );
document.write( "sin(x + y) = <BR>\n" );
document.write( "cos(x + y) = <BR>\n" );
document.write( "tan(x + y) = </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #560192 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=560192\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose sin x = 1/7 cos x > 0,<BR>\n" );
document.write( "Note: cos(x) = sqrt(49-1)/7 = sqrt(48)/7<BR>\n" );
document.write( "----------------------------------------------- <BR>\n" );
document.write( "sin y = &#8722;2/5 and cos y < 0.<BR>\n" );
document.write( "Note: cos(y) = -sqrt(25-4)/5 = -sqrt(21)/5<BR>\n" );
document.write( "------------------------------ <BR>\n" );
document.write( "Then <BR>\n" );
document.write( "cos x = 4sqrt(3)/7<BR>\n" );
document.write( "cos y = -sqrt(21)/5<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "Find each of the following quantities: <BR>\n" );
document.write( "sin(x + y) = sin(x)cos(y)+cos(x)sin(y)<BR>\n" );
document.write( "Substitute to get the numerical answer.<BR>\n" );
document.write( "-----<BR>\n" );
document.write( "cos(x + y) = cos(x)cos(y)-sin(x)sin(y)<BR>\n" );
document.write( "Substitute:: <BR>\n" );
document.write( "tan(x + y) =<BR>\n" );
document.write( "Divide sin(x+y) by cos(x+y)<BR>\n" );
document.write( "==================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "=============== </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );