document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1026523>Question 1026523</A>: <I><SPAN STYLE=\"word-break: break-all;\"> PLEASE HELP ME ! \r<BR>\n" );
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document.write( "Find sin 2x, cos 2x, and tan 2x from the given information.<BR>\n" );
document.write( "tan x = &#8722; 15/8 ,   x in Quadrant II </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #641754 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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/cgi-bin/show-face.mpl?user=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=641754\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> tan^(-1) of -15/8 is approx -62 degrees<BR>\n" );
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document.write( "trig functions are periodic - we are looking for the angle in the second quadrant which is equivalent to -62 degrees, that angle is 180-62 = 118 degrees<BR>\n" );
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document.write( "sin(118) = 0.88<BR>\n" );
document.write( "cos(118) = -0.47<BR>\n" );
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document.write( "sin 2x = 2sin(x)cos(x)<BR>\n" );
document.write( "sin 2x = 2(0.88)(-0.47) = -0.83<BR>\n" );
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document.write( "cos 2x = 2cos^2(x) - 1<BR>\n" );
document.write( "cos 2x = 2(-0.47)^2 - 1 = -0.56<BR>\n" );
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document.write( "tan 2x = (2tan(x)) / (1 - tan^2(x))<BR>\n" );
document.write( "tan 2x = (2(-15/8)) / (1 - (-15/8)^2) = 1.49<BR>\n" );
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