Let un+1=2un+1, (n=0,1,2,....) and u0=0. Then u10would be nearest to: (CAT 1993)
un+1=2un+1, (n=0,1,2,....)
Put n = 0, u1 = 1
n = 1, u2 = 3
n = 2, u3 = 7
n = 3, u4 = 15
n = 4, u5 = 31
Seeing the pattern it is clear that un=2n−1
Hence ,u10=(2)10−1=1,023.