document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1162185>Question 1162185</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use an Addition or Subtraction Formula to write the expression as a trigonometric function of one number.<BR>\n" );
document.write( "sin(4π/7) cos(5π/21) − cos(4π/7) sin(5π/21)\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #785923 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13203)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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/cgi-bin/show-face.mpl?user=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=785923\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%28A%29cos%28B%29-cos%28A%29sin%28B%29+=+sin%28A-B%29 ALIGN=MIDDLE  ALT=\"sin%28A%29cos%28B%29-cos%28A%29sin%28B%29+=+sin%28A-B%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Plug in the numbers:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin%284pi%2F7%29cos%285pi%2F21%29-cos%284pi%2F7%29sin%285pi%2F21%29+=+sin%284pi%2F7-5pi%2F21%29 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "You can finish....<br> </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );