The operation Δ is defined for all nonzero x and y by x Δ y ~$=x+\frac{x}{y}$~ . If a > o, then 1 Δ (1 Δ a) =
a
a+1
~$\frac{a}{a+1}$~
~$\frac{a+2}{a+1}$~
~$\frac{2a+1}{a+1}$~
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