document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=863135>Question 863135</A>: <I><SPAN STYLE=\"word-break: break-all;\"> How do I find the cos(5pi/12)?! The question says \"Use the sum or difference formula to determine the value of the trigonometric function\"\r<BR>\n" );
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document.write( "Thank you! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #520233 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=520233\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> How do I find the cos(5pi/12)?! The question says \"Use the sum or difference formula to determine the value of the trigonometric function\"<BR>\n" );
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document.write( "cos(5&#960;/12)=cos(2&#960;/12+3&#960;/12)=cos(&#960;/6+&#960;/4)<BR>\n" );
document.write( "Identity: cos(x+y)=cosxcosy-sinxsiny)<BR>\n" );
document.write( "cosx=cos(&#960;/6)=&#8730;3/2<BR>\n" );
document.write( "cosy=cos(&#960;/4)=&#8730;2/2<BR>\n" );
document.write( "sinx=sin(&#960;/6)=1/2<BR>\n" );
document.write( "siny=sin(&#960;/4)=&#8730;2/2<BR>\n" );
document.write( "cos(x+y)=&#8730;3/2*&#8730;2/2-1/2*&#8730;2/2=&#8730;6/4-&#8730;2/4=(&#8730;6-&#8730;2)/4<BR>\n" );
document.write( "...<BR>\n" );
document.write( "calculator check:<BR>\n" );
document.write( "cos(5&#960;/12)&#8776;0.2588…<BR>\n" );
document.write( "exact value=(&#8730;6-&#8730;2)/4&#8776;0.2588… </SPAN>\n" );
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