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sprinkle

sin(y-x)=5/13 => cos(y-x) = 12/13 => tan(y-x) = 5/12

cos(y+x)=4/5 => sin(y+x) = 3/5 => tan(y+x) = 3/4

tan 2y = tan ((x+y) + (y-x)) = (tan(x+y) + tan(y-x))/(1 - tan(x+y)*tan(y-x))

                                        = (3/4 + 5/12)/(1 - (3/4) * (5/12))

                                        = (14/12)/(11/16) = 56/33

   (sorry for mis-calculations if any

, as ans is not matching with previous ones)

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