document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=974506>Question 974506</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Prove cos(x+pi) is equivalent to -cos(x). Thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #596401 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=596401\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Prove cos(x+pi) is equivalent to -cos(x)<BR>\n" );
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document.write( "cos(x+pi) = cos(x)*cos(pi) - sin(x)*sin(pi)<BR>\n" );
document.write( "= cos(x)*(-1) - sin(x)*0<BR>\n" );
document.write( "= -cos(x) </SPAN>\n" );
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