A sequence x0, x1, x2, x3, …. is defined by letting x0 = 5 and
xk =4+xk–1 for all natural numbers k. Show that xn = 5 for all
nϵN using mathematical induction.
Let P(n): xn =5+4n for all nϵN
Step1: For n=0,
P(0):x0=5+4×0=5
So, it is true for n=0.
Step2: Let P(k) be true
Thus, xk =5+4k
Now, we need to show P(k+1) is true whenever P(k) is true.
P(k+1):
xk+1 =4+ xk+1-1
=4+xk
=4+5+4k
=5+4(k+1)
=RHS
Thus, P(k+1) is true, so by mathematical induction P(n) is true.