document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=440916>Question 440916</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if sin x=4/5, where x is greater than 0 but less than 90  evaluate each of the following<BR>\n" );
document.write( "a) sin 2x<BR>\n" );
document.write( "b) cos 2x<BR>\n" );
document.write( "c) tan 2x  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #305406 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=305406\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> if sin x=4/5, where x is greater than 0 but less than 90 evaluate each of the following<BR>\n" );
document.write( "a) sin 2x<BR>\n" );
document.write( "b) cos 2x<BR>\n" );
document.write( "c) tan 2x<BR>\n" );
document.write( "..<BR>\n" );
document.write( "If sin x=4/5, we are working with a 3-4-5 right triangle in quadrant I<BR>\n" );
document.write( "Then, cos x=3/5<BR>\n" );
document.write( "tan x=4/3<BR>\n" );
document.write( "..<BR>\n" );
document.write( "a) sin 2x=2sin x cos x=2*4/5*3/5=24/25\r<BR>\n" );
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document.write( "b) cos 2x=cos^2x -sin^2x=(3/5)^2-(4/5)^2=9/25-16/25=-7/25\r<BR>\n" );
document.write( "\n" );
document.write( "c) tan 2x=2tanx/1-tan^2x=2*(4/3)/1-(4/3)^2<BR>\n" );
document.write( "              =(8/3)/1-16/9<BR>\n" );
document.write( "              =(8/3)/-7/9=-72/21<BR>\n" );
document.write( "..<BR>\n" );
document.write( "ans:<BR>\n" );
document.write( "a) sin 2x=24/25<BR>\n" );
document.write( "b) cos 2x=-7/25<BR>\n" );
document.write( "c) tan 2x=-72/21 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );