In this section 11th grade math, student will learn the new topic prove by mathematical induction.
In algebra or in other disciplines of mathematics, there are certain results or statements that are formulated in terms of 'n' is a positive integer. To prove such statements, well suited method based on the specific technique is known as the Principle of Mathematical Induction.
ii) P(k) is true, then P(k+1) is also true, where k is a natural number.
Then the statement P(n) is true for every natural number n.
Example 1 : Show that n 3 + (n+1) 3 + (n+2) 3 is divisible by 9 for every natural number 'n'.
First we will verify P(1) is true.
P(k) is true. -------(equation 2) that means P(k): k 3 + (k+1) 3 +(k+2) 3 is divisible by 9.
Now we want to prove that P(k+1) is true.
From equation (2), (k+1) 3 + (k+2) 3 +k 3 is divisible by 9 and 9(k 2 + 3k +3)is also divisible by 9.
n 3 + (n+1) 3 + (n+2) 3 is divisible by 9.
Example 2 : Show that the sum of the first 'n' odd natural numbers is n 2 .
Assume that P(k) is true.
Now we have to prove that P(k+1) is true.
∴ P(k+1) is true whenever p(k) is true.
Hence by equation (1), (2) and by principle of mathematical induction P(n) is true for all natural number 'n'.