document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=737089>Question 737089</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Use the given information to find cos 2x, sin 2x, and tan 2x. <BR>\n" );
document.write( "cosx=sqrt3/7 and 3&#960;/2 < x < 2&#960;\r<BR>\n" );
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document.write( "since I have cos, I created a triangle using sqrt3 as the opposite side. and 7 as the adjacent side.  Then I used the Pythagorean theorem to find the hypotenuse.<BR>\n" );
document.write( "hypotenuse^2=(sqrt3)^2+(7)^2<BR>\n" );
document.write( "hypotenuse^2=3+49<BR>\n" );
document.write( "hypotenuse^2=52<BR>\n" );
document.write( "hypotenuse=sqrt52\r<BR>\n" );
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document.write( "Then to find sin2x, I used sin2x=2sin(xcos(x), so...<BR>\n" );
document.write( "sin2x=2sin(xcos(x)<BR>\n" );
document.write( "= 2(sqrt3/sqrt52)(sqrt3/7)<BR>\n" );
document.write( "= 2 (sqrt9/7sqrt52)<BR>\n" );
document.write( "= 3/7sqrt13\r<BR>\n" );
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document.write( "but that was incorrect and I can't go any further in the problem with an incorrect sin2x.  Please assist me with where I went wrong or how to go about finding this answer. thanks!<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #450182 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=450182\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> cos x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%283%29%2F7 ALIGN=MIDDLE  ALT=\"sqrt%283%29%2F7\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "square both sides\r<BR>\n" );
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document.write( "cos^2 x=3/49\r<BR>\n" );
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document.write( "1-cos^2 x=1-3/49\r<BR>\n" );
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document.write( "sin^2 x = 46/49\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sin+x=+-sqrt%2846%29%2F7 ALIGN=MIDDLE  ALT=\"sin+x=+-sqrt%2846%29%2F7\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "cos 2x = 2 cos^2 x -1\r<BR>\n" );
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document.write( "=2*3/49-1<BR>\n" );
document.write( "=6/49-1\r<BR>\n" );
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document.write( "=-43/49\r<BR>\n" );
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document.write( "Cos 2x= -43/49\r<BR>\n" );
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document.write( "Sin 2x = 2sin x . cos x\r<BR>\n" );
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document.write( "=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2A%28-sqrt%2847%29%2F7%29+%2A%28sqrt%283%29%2F7%29 ALIGN=MIDDLE  ALT=\"2%2A%28-sqrt%2847%29%2F7%29+%2A%28sqrt%283%29%2F7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "=<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2Asqrt%28141%29%2F49 ALIGN=MIDDLE  ALT=\"2%2Asqrt%28141%29%2F49\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Tan (2x) = sin (2x)/cos (2x)\r<BR>\n" );
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