document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=453317>Question 453317</A>: <I><SPAN STYLE=\"word-break: break-all;\"> find cos x/2, given: sin x = 1/4, 360 < x < 450, use half-angle identity to find the exact value. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #311535 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=311535\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> find cos x/2, given: sin x = 1/4, 360 < x < 450<BR>\n" );
document.write( "------<BR>\n" );
document.write( "cos(x/2) = +/- sqrt[(1+cos(x))/2]<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Since sin(x) = 1/4, y = 1 and r = 4<BR>\n" );
document.write( "---<BR>\n" );
document.write( "So x = sqrt[4^2-1^2] = sqrt(15)<BR>\n" );
document.write( "----<BR>\n" );
document.write( "Therefore cos(x) = x/r = sqrt(15)/4<BR>\n" );
document.write( "=====<BR>\n" );
document.write( "So, cos(x/2) = +/- sqrt[(1+[sqrt(15)/4]]/2]<BR>\n" );
document.write( "=======================================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "===============<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );