Question 1172165:  Find the exact values of  sin(2u), cos(2u), and tan(2u) using the double-angle formulas.
 
csc(u) = 6,   0 < u < 𝜋/2
 
sin(2u)	 = 	 
  
cos(2u)	 = 	 
  
tan(2u)	 = 
 Found 3 solutions by  Boreal, MathTherapy, Alan3354: Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! sin 2u=2 sin u  cos u; 
csc u =6, sin u =1/6, u=9.59 degrees 
cos u has to be sqrt(35)/6 
sin 2u=2 sqrt(35)/36=sqrt(35)/18 
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cos (2u)=cos ^2 u-sin^2 u 
=(35/36)-(1/36)=17/18 
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tan 2u= sin 2u / cos 2u 
=sqrt(35)/17 
or 2 tan (u)/1-tan^2 (u) 
where tan u = 1/sqrt(35)=sqrt(35)/35 
so 2 sqrt(35)/35/1-35/35^2; the denominator is (35^2-35/35^2) 
this will become 2 sqrt(35)*35/1190, and that is 2 sqrt(35)/34 or sqrt(35)/17), same as above. sin u/ cos u is easier, since those have already been obtained. 
 Answer by MathTherapy(10557)      (Show Source):  Answer by Alan3354(69443)      (Show Source): 
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