I think the solution is easy, but I´m missing the last thought to solve it.
9. If the sequence x1, x2, x3, …, xn, … is such that x1 = 3 and xn+1= 2xn – 1 for n ≥ 1, then x20 – x19 equals?
a) 219
b) 220
c) 221
d) 220 – 1
e) 221 – 1
The answer is A. Maybe you can help me with this one.
9. If the sequence x1, x2, x3, …, xn, … is such that x1 = 3 and xn+1= 2xn – 1 for n ≥ 1, then x20 – x19 equals?
a) 219
b) 220
c) 221
d) 220 – 1
e) 221 – 1
The answer is A. Maybe you can help me with this one.
