document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=449095>Question 449095</A>: <I><SPAN STYLE=\"word-break: break-all;\">  <BR>\n" );
document.write( "what is the value of the following function? cos(130°)cos(10°) + sin(10°) sin(130°).<BR>\n" );
document.write( "  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #309027 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=309027\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> what is the value of the following function? cos(130°)cos(10°) + sin(10°) sin(130°).<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Addition formula for cosine:<BR>\n" );
document.write( "cos(s-t)=cos s cos t+sin s sin t<BR>\n" );
document.write( "For given equation:<BR>\n" );
document.write( "cos(130°)cos(10°) + sin(130°) sin(10°)=cos(130º-10º)=cos 120º<BR>\n" );
document.write( "In standard position 120º terminates in quadrant II where cos is negative.<BR>\n" );
document.write( "reference angle=180-120 =60º<BR>\n" );
document.write( "cos 60º=-1/2 </SPAN>\n" );
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