document.write( "Question 810474: Find sin (2x), cos (2x), and tan (2x) from the given information. \r
\n" ); document.write( "\n" ); document.write( "sec (x) = 10\r
\n" ); document.write( "\n" ); document.write( "x in quadrant 4 \n" ); document.write( "
Algebra.Com's Answer #488344 by lwsshak3(11628)\"\" \"About 
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Find sin (2x), cos (2x), and tan (2x) from the given information.
\n" ); document.write( "sec (x) = 10, x in quadrant 4
\n" ); document.write( "***
\n" ); document.write( "secx=10=1/cosx
\n" ); document.write( "cosx=1/10
\n" ); document.write( "sinx=√(1-cos^2x)=√(1-1/100)=√(99/100)=-√99/10
\n" ); document.write( "tanx=sinx/cosx=√99/1=-√99
\n" ); document.write( "..
\n" ); document.write( "sin(2x)=2sinxcosx=2*-√99/10*1/10=-2√99/100=-√99/50
\n" ); document.write( "cos(2x)=cos^2x-sin^2x=1/100-99/100=-98/100=-49/50
\n" ); document.write( "tan(2x)=2tanx/1-tan^2x=2*-√99/(1-99)=-2√99/-98=√99/49
\n" ); document.write( "...
\n" ); document.write( "Check(w/calculator)
\n" ); document.write( "cosx=1/10(in quadrant IV where cos>0
\n" ); document.write( "x=275.7392
\n" ); document.write( "2x=551.478
\n" ); document.write( "..
\n" ); document.write( "sin(2x)=sin(551.4783)≈-0.1989..
\n" ); document.write( "Exact answer=-√99/50≈-0.1989..
\n" ); document.write( "..
\n" ); document.write( "cos(2x)=cos(551.4783)≈-0.9800..
\n" ); document.write( "Exact answer=-49/50≈-0.9800..
\n" ); document.write( "..
\n" ); document.write( "tan(2x)=tan(551.4783)≈0.2031..
\n" ); document.write( "Exact answer=-49/50≈0.2031.. \n" ); document.write( "
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