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| Question 967184:  Find sin 2x, cos 2x, and tan 2x from the given information.
 tan x = −1/6,   cos x > 0
 
 sin 2x	=
 cos 2x	=
 tan 2x	=
 Answer by lwsshak3(11628)
      (Show Source): 
You can put this solution on YOUR website! Find sin 2x, cos 2x, and tan 2x from the given information. tan x = −1/6, cos x > 0
 reference angle x is in quadrant IV where cos>0, sin<0
 hypotenuse of reference right triangle in quadrant IV=√(6^2+1^2)=√(36+1)=√37
 sinx=-1/√37=-√37/37
 cosx=6/√37=(6√37)/37
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 sin(2x)=2sinxcosx=2*-√37/37*6√37/37=-444/1369
 cos(2x)=cos^2(x)-sin^2(x)=36/37-1/37=35/37
 tan(2x)=sin(2x)/cos(2x)=16428/47915
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 Check:
 tanx=1/6(Q4)
 x=350.538
 2x=701.075
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 sin(2x)=sin(701.075)=-0.3243
 exact value as computed=-444/1369≈-0.3243
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 cos(2x)=cos(701.075)=0.9459
 exact value as computed=35/37≈0.9459
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