Prove the following by using the principle of mathematical induction for all
.
Let P(n):
I. For n =1,
∴ P(1) is true.
II. Suppose the statement is true for n = m,
∴
III. For n = m + 1,
or 1.2.3 + 2.3.4 + 3.4.5 + ........... + m (m + 1) (m + 2) + (m + 1) (m + 2) (m + 3)
From (i), 1.2.3 + 2.3.4 + 3.4.5 + ......... + m (m + 1) (m + 2)
∴
which is true.
∴ P(m + 1) is true.
∴ P(m) is true P(m + 1) is true.
Hence, by the principle of mathematical induction, P(n) is true for all