document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=42455>Question 42455</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the exact value of cos 105º by using a half-angle formula.\r<BR>\n" );
document.write( "\n" );
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 #28163 by </B><A HREF=/tutors/aboutme.mpl?userid=psbhowmick><B>psbhowmick(878)</B></A><img src=\"/images/stars/stars-11.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=psbhowmick><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=psbhowmick><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=28163\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28105%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%28105%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28180%5Eo+-+75%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%28180%5Eo+-+75%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-cos%2875%5Eo%29 ALIGN=MIDDLE  ALT=\"-cos%2875%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Now, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%2875%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%2875%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%2830%5Eo+%2B+45%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%2830%5Eo+%2B+45%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%2830%5Eo%29cos%2845%5Eo%29+-+sin%2830%5Eo%29sin%2845%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%2830%5Eo%29cos%2845%5Eo%29+-+sin%2830%5Eo%29sin%2845%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28sqrt%283%29%2F2%29%2A%281%2Fsqrt%282%29%29+-+%281%2F2%29%2A%281%2Fsqrt%282%29%29 ALIGN=MIDDLE  ALT=\"%28sqrt%283%29%2F2%29%2A%281%2Fsqrt%282%29%29+-+%281%2F2%29%2A%281%2Fsqrt%282%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%283%29%2F%282%2Asqrt%282%29%29+-+1%2F%282%2Asqrt%282%29%29 ALIGN=MIDDLE  ALT=\"sqrt%283%29%2F%282%2Asqrt%282%29%29+-+1%2F%282%2Asqrt%282%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28sqrt%283%29-1%29%2F%282sqrt%282%29%29 ALIGN=MIDDLE  ALT=\"%28sqrt%283%29-1%29%2F%282sqrt%282%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Hence, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=cos%28105%5Eo%29 ALIGN=MIDDLE  ALT=\"cos%28105%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-cos%2875%5Eo%29 ALIGN=MIDDLE  ALT=\"-cos%2875%5Eo%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "= <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-%28sqrt%283%29-1%29%2F%282sqrt%282%29%29 ALIGN=MIDDLE  ALT=\"-%28sqrt%283%29-1%29%2F%282sqrt%282%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " <u> <BR>\n" );
document.write( "VVI<BR>\n" );
document.write( "No irratonal number can have any exact value. As the answer is an irrational fraction so its value is always approximate. For more detailed discussion on rational and irrational numbers see my lesson on \"Rational & Irrational Numbers\" at <BR>\n" );
document.write( "http://www.algebra.com/tutors/lessons-by-tutor.mpl?tutor=psbhowmick </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );