document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=729251>Question 729251</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use a half-angle identity to exactly evaluate the trigonometric expression: tan -3pi/8 </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #445883 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=445883\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Use a half-angle identity to exactly evaluate the trigonometric expression: tan -3pi/8<BR>\n" );
document.write( "***<BR>\n" );
document.write( "tan(-3&#960;/8)=-tan(3&#960;/4)/2<BR>\n" );
document.write( "=-(sin3&#960;/4)/(1+cos3&#960;/4)<BR>\n" );
document.write( "=-[&#8730;2/2/(1+(-&#8730;2/2)]<BR>\n" );
document.write( "=-(&#8730;2/2)/(1-&#8730;2/2)<BR>\n" );
document.write( "check with calculator:<BR>\n" );
document.write( "tan(-3&#960;/8)&#8776;-2.4142..<BR>\n" );
document.write( "-(&#8730;2/2)/(1-&#8730;2/2)&#8776;--2.4142.. </SPAN>\n" );
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