A sequence (x_0, x_1, x_2, x_3, ......) is defined by letting x0=5 and xk=4+xk−1 for all natural numbers k. Show that xn = 5 + 4n for all n ϵ N using mathematical induction.
Consider the given statement
P(n) : bn=5+4n, for all natural numbers
given that b0=5 and bk=4+bk−1
Step I P(1) is true.
P(1) : b1=5+4×1=9
As b0=5, b1=4+b0=4+5=9
Hence, P(1) is true.
Step II Now, assume that P(n) is true for n = k
P(k) : bk=5+4k
Step III Now, to prove P(k + 1) is true, we have to show that
∴ P(k+1):bk+1=5+4(k+1)
bk+1=4+bk+1−1
=4+bk
=4+5+4k=5+4(k+1)
So, by the mathematical induction P(k + 1) is ture whanever P(k) is true, hence P(n) is true.