document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=756970>Question 756970</A>: <I><SPAN STYLE=\"word-break: break-all;\"> prove this equation to be an identity;\r<BR>\n" );
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document.write( "(sin(3x/7))(cos(4x/7)) + (cos(3x/7))(sin(4x/7)) = sin(x) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #460676 by </B><A HREF=/tutors/aboutme.mpl?userid=tommyt3rd><B>tommyt3rd(5050)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=tommyt3rd><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=tommyt3rd><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=460676\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Angle sum formula:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%0D%0Asin%28x%2By%29=sin%28x%29cos%28y%29-cos%28x%29sin%28y%29%0D%0A ALIGN=MIDDLE  ALT=\"%0D%0Asin%28x%2By%29=sin%28x%29cos%28y%29-cos%28x%29sin%28y%29%0D%0A\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "the two angles are 3x/7 and 4x/7\r<BR>\n" );
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document.write( "therefore their sum is x\r<BR>\n" );
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