document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=683117>Question 683117</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please solve equation without using a calculator. Show all work<BR>\n" );
document.write( " {{Cos(2sin^-1(1/4)}} </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #423477 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=423477\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Please solve equation without using a calculator. Show all work<BR>\n" );
document.write( "{{Cos(2sin^-1(1/4)}}<BR>\n" );
document.write( "sin^-1(1/4)=an angle x whose sin=1/4<BR>\n" );
document.write( "Cos(2sin^-1(1/4)=cos2x<BR>\n" );
document.write( "=1-2sin^2x=1-2*(1/4)^2<BR>\n" );
document.write( "=1-(2/16)<BR>\n" );
document.write( "=1-(1/8)<BR>\n" );
document.write( "=7/8<BR>\n" );
document.write( "check with calculator:<BR>\n" );
document.write( "2sin^-1(1/4)&#8776;.2527*2&#8776;.5054<BR>\n" );
document.write( "cos(.5054)&#8776;.875=7/8 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );