document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=870529>Question 870529</A>: <I><SPAN STYLE=\"word-break: break-all;\"> if sinx= -4/5 on the interval (pi , 3pi/2) what is the exact value of 2x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #525164 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=525164\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> if sinx= -4/5 on the interval (pi , 3pi/2) what is the exact value of 2x<BR>\n" );
document.write( "you are working with a (3-4-5) reference right triangle in quadrant III<BR>\n" );
document.write( "cosx=-3/5<BR>\n" );
document.write( "cos 2x=cos^2x-sin^2x=(-3/5)^2-(4/5)^2=9/25-16/25=-7/25<BR>\n" );
document.write( "cos 2x=-7/25<BR>\n" );
document.write( "2x&#8776;106.26&#730; </SPAN>\n" );
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