Using the principle of mathematical induction, prove each of the following for all n ϵ N:

3.22 + 32.23 + 33.24 + …. + 3n.2n+1 = (6n – 1).


To Prove:



Let us prove this question by principle of mathematical induction (PMI)


Let P(n):


For n = 1


LHS = = 12


RHS =


= = 12


Hence, LHS = RHS


P(n) is true for n = 1


Assume P(k) is true


……(1)


We will prove that P(k + 1) is true




…(2)


We have to prove P(k + 1) from P(k) ie (2) from (1)


From (1)



Adding both sides









which is the same as P(k + 1)


Therefore, P (k + 1) is true whenever P(k) is true.


By the principle of mathematical induction, P(n) is true for×


where n is a natural number


Put k = n - 1




Hence proved


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