document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=616888>Question 616888</A>: <I><SPAN STYLE=\"word-break: break-all;\"> im completely lost on how to work these out,\r<BR>\n" );
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document.write( "Given cos A =0.42 and sin B = 0.73 evaluate \r<BR>\n" );
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document.write( "(a) sin(A - B)<BR>\n" );
document.write( "(b) cos(A - B)<BR>\n" );
document.write( "(c) tan(A+B)\r<BR>\n" );
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document.write( "to 4 decimal places </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #387943 by </B><A HREF=/tutors/aboutme.mpl?userid=jsmallt9><B>jsmallt9(3758)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jsmallt9><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=387943\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In order to solve these problems, we will need to be able to figure out what cos(B) and sin(A) are.<br><BR>\n" );
document.write( "We're told that cos(A) = 0.42. Cos is positive in both the 1st and 4th quadrants. sin(A) will be positive if A terminates in the 1st quadrant but it will be negative if A terminates in the 4th.<br><BR>\n" );
document.write( "Similarly, we cannot figure out the sign of cos(B) without knowing where B terminates.<br><BR>\n" );
document.write( "So without information that could be used to determine the quadrants for A and B, these problems cannot be done. Either you or your teacher have left out something important. </SPAN>\n" );
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