For which equality in the following calculation does the induction hypothesis get used? 1. zu, ari = (sk_gar) +ark+1 2. (Ekar) + apk+1 = = (ark+1 a)/(r 1) + ark+1 3. (ark+1 a)/(r 1) a By induction hypothesis + ark+1 = (ark+1 + ark+1 (r 1))/(r 1) 4. (ark+1 a + ark+1(r 1)) lr 1) = (ark+1 + ark+2 ark+l))/(r 1) a 5. (ark+1 a + ark+2 ark+l))/(r 1) (ark+2 a)/(r 1) =