Question
Prove the following by using the principle of mathematical induction for all is a multiple of 27 for all
Solution
Let P(n): is a multiple of 27.
I. For n = 1,
P(1): is a multiple of 27
41 - 14 is a multiple of 27
27 is a multiple of 27
which is true.
∴ P(n) is true for n = 1
II. Suppose P(n) is true for n = m, P(m) :
is a multiple of 27
...(i)
III. For n = m + 1,
P (m + 1) : is a multiple of 27
But,
= [By (i)]
where
is a multiple of 27
∴ P(m + 1) is true.
∴ P(m) is true P(m + 1) is true.
Hence, by induction, P(n) is true for all