document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=610303>Question 610303</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Find the exact values of sin(2theta), and cos(2theta) if sin(theta)= -9/10 and theta is between 180 degrees and 270 degrees. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #384330 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=384330\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the exact values of sin(2theta), and cos(2theta) if sin(theta)= -9/10 and theta is between 180 degrees and 270 degrees.<BR>\n" );
document.write( "**<BR>\n" );
document.write( "use x in place of theta.<BR>\n" );
document.write( "sinx=-9/10=opposite side/hypotenuse (in quadrant III where sin is <0)<BR>\n" );
document.write( "Adjacent side=&#8730;(10^2-9^2)=&#8730;(100-81)=&#8730;19<BR>\n" );
document.write( "cosx=-&#8730;19/10  (in quadrant III where cos is also<0)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "sin2x=2sinxcosx<BR>\n" );
document.write( "=2*(-9/10)*(-&#8730;19/10)<BR>\n" );
document.write( "=18&#8730;19/100<BR>\n" );
document.write( "=(9&#8730;19)/50 (in quadrant II where sin>0)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "cos2x=cos^2x-sin^2x<BR>\n" );
document.write( "=(-&#8730;19/10)^2-(-9/10)^2<BR>\n" );
document.write( "=19/100-81/100<BR>\n" );
document.write( "=-62/100<BR>\n" );
document.write( "=-31/50  (in quadrant II where cos<0) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );