In This Post we are  providing Chapter – 4 Principle of Mathemarical Induction NCERT Solutions for Class 11 Maths which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These  Class 11  Principle of Mathemarical Induction solutions can be really helpful in the preparation of Board exams and will provide you with in depth detail of the chapter.

We have solved every question stepwise so you don’t have to face difficulty in understanding the solutions. It will also give you concepts that are important for overall development of students. Class 11 Maths  Principle of Mathemarical Induction NCERT Written Solutions  will be useful in higher classes as well because variety of questions related to these concepts can be asked so you must study and understand them properly.

Class 11th Chapter 4 Principle of Mathemarical Induction| NCERT MATHS SOLUTION |

Chapter 4 Principle of Mathemarical Induction EX 4.1 NCERT Solutions

Prove the following by using the principle of mathematical induction for aline n ∈ N :
Ex 4.1 Class 11 Maths Question 1.
1+{ 3 }^{ 2 }+{ 3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ 3 }^{ n }=frac { left( { 3 }^{ n }-1 right) }{ 2 }


Solution.
Let the given statement be P(n) i.e.,
P(n) : 1+{ 3 }^{ 2 }+{ 3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ 3 }^{ n }=frac { left( { 3 }^{ n }-1 right) }{ 2 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 1NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 2

Ex 4.1 Class 11 Maths Question 2.
{ 1 }^{ 3 }+{ 2 }^{ 3 }+{ 3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ n }^{ 3 }={ left( frac { nleft( n+1 right) }{ 2 } right) }^{ 2 }
Solution.
Let the given statement be P(n) i.e.,
P(n) : { 1 }^{ 3 }+{ 2 }^{ 3 }+{ 3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ n }^{ 3 }={ left( frac { nleft( n+1 right) }{ 2 } right) }^{ 2 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 3NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 4

Ex 4.1 Class 11 Maths Question 3.
1+frac { 1 }{ left( 1+2 right) } +frac { 1 }{ left( 1+2+3 right) } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 1+2+3+cdot cdot cdot cdot cdot cdot cdot cdot +n right) } =frac { 2 }{ left( n+1 right) }
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1+frac { 1 }{ left( 1+2 right) } +frac { 1 }{ left( 1+2+3 right) } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 1+2+3+.cdot cdot cdot cdot cdot cdot cdot cdot +n right) } =frac { 2 }{ left( n+1 right) }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 5NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 6

Ex 4.1 Class 11 Maths Question 4.
1.2.3+2.3.4+cdot cdot cdot cdot cdot cdot cdot cdot +nleft( n+1 right) left( n+2 right) =frac { nleft( n+1 right) left( n+2 right) left( n+3 right) }{ 4 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1.2.3+2.3.4+cdot cdot cdot cdot cdot cdot cdot cdot +nleft( n+1 right) left( n+2 right) =frac { nleft( n+1 right) left( n+2 right) left( n+3 right) }{ 4 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 7NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 8

Ex 4.1 Class 11 Maths Question 5.
1.3+{ 2.3 }^{ 2 }+{ 3.3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ n.3 }^{ n }=frac { left( 2n-1 right) { 3 }^{ n+1 }+3 }{ 4 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1.3+{ 2.3 }^{ 2 }+{ 3.3 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ n.3 }^{ n }=frac { left( 2n-1 right) { 3 }^{ n+1 }+3 }{ 4 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 9NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 10

Ex 4.1 Class 11 Maths Question 6.
1.2+2.3+3.4+cdot cdot cdot cdot cdot cdot cdot cdot +n.left( n+1 right) =left[ frac { nleft( n+1 right) left( n+2 right) }{ 3 } right]
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1.2+2.3+3.4+cdot cdot cdot cdot cdot cdot cdot cdot +n.left( n+1 right) =left[ frac { nleft( n+1 right) left( n+2 right) }{ 3 } right]
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 11NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 12

Ex 4.1 Class 11 Maths Question 7.
1.3+3.5+5.7+cdot cdot cdot cdot cdot cdot cdot cdot +left( 2n-1 right) left( 2n+1 right) =frac { nleft( { 4n }^{ 2 }+6n-1 right) }{ 3 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1.3+3.5+5.7+cdot cdot cdot cdot cdot cdot cdot cdot +left( 2n-1 right) left( 2n+1 right) =frac { nleft( { 4n }^{ 2 }+6n-1 right) }{ 3 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 13NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 14NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 15

Ex 4.1 Class 11 Maths Question 8.
1.2+2.{ 2 }^{ 2 }+3.{ 2 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +n.{ 2 }^{ n }=left( n-1 right) { 2 }^{ n+1 }+2
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1.2+2.{ 2 }^{ 2 }+3.{ 2 }^{ 3 }+cdot cdot cdot cdot cdot cdot cdot cdot +n.{ 2 }^{ n }=left( n-1 right) { 2 }^{ n+1 }+2
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 16

Ex 4.1 Class 11 Maths Question 9
frac { 1 }{ 2 } +frac { 1 }{ 4 } +frac { 1 }{ 8 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ { 2 }^{ n } } =1-frac { 1 }{ { 2 }^{ n } }
Solution.
Let the given statement be P(n), i.e.,
P(n) : frac { 1 }{ 2 } +frac { 1 }{ 4 } +frac { 1 }{ 8 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ { 2 }^{ n } } =1-frac { 1 }{ { 2 }^{ n } }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 17NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 18

Ex 4.1 Class 11 Maths Question 10.
frac { 1 }{ 2.5 } +frac { 1 }{ 5.8 } +frac { 1 }{ 8.11 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 3n-1 right) left( 3n+2 right) } =frac { n }{ left( 6n+4 right) }
Solution.
Let the given statement be P(n), i.e.,
P(n) : frac { 1 }{ 2.5 } +frac { 1 }{ 5.8 } +frac { 1 }{ 8.11 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 3n-1 right) left( 3n+2 right) } =frac { n }{ left( 6n+4 right) }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 19NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 20

Ex 4.1 Class 11 Maths Question 11.
frac { 1 }{ 1.2.3 } +frac { 1 }{ 2.3.4 } +frac { 1 }{ 3.4.5 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ nleft( n+1 right) left( n+2 right) } =frac { nleft( n+3 right) }{ 4left( n+1 right) left( n+2 right) }
Solution.
Let the given statement be P(n), i.e.,
P(n) : frac { 1 }{ 1.2.3 } +frac { 1 }{ 2.3.4 } +frac { 1 }{ 3.4.5 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ nleft( n+1 right) left( n+2 right) } =frac { nleft( n+3 right) }{ 4left( n+1 right) left( n+2 right) }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 21NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 22NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 23

Ex 4.1 Class 11 Maths Question 12.
a+ar+{ ar }^{ 2 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ ar }^{ n-1 }=frac { aleft( { r }^{ n }-1 right) }{ r-1 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : a+ar+{ ar }^{ 2 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ ar }^{ n-1 }=frac { aleft( { r }^{ n }-1 right) }{ r-1 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 24NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 25

Ex 4.1 Class 11 Maths Question 13.
left( 1+frac { 3 }{ 1 } right) left( 1+frac { 5 }{ 4 } right) left( 1+frac { 7 }{ 9 } right) cdot cdot cdot cdot cdot cdot cdot cdot left( 1+frac { left( 2n+1 right) }{ { n }^{ 2 } } right) ={ left( n+1 right) }^{ 2 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : left( 1+frac { 3 }{ 1 } right) left( 1+frac { 5 }{ 4 } right) left( 1+frac { 7 }{ 9 } right) cdot cdot cdot cdot cdot cdot cdot cdot left( 1+frac { left( 2n+1 right) }{ { n }^{ 2 } } right) ={ left( n+1 right) }^{ 2 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 26NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 27

Ex 4.1 Class 11 Maths Question 14.
left( 1+frac { 1 }{ 1 } right) left( 1+frac { 1 }{ 2 } right) left( 1+frac { 1 }{ 3 } right) cdot cdot cdot cdot cdot cdot cdot cdot left( 1+frac { 1 }{ n } right) =left( n+1 right)
Solution.
Let the given statement be P(n), i.e.,
P(n) : left( 1+frac { 1 }{ 1 } right) left( 1+frac { 1 }{ 2 } right) left( 1+frac { 1 }{ 3 } right) cdot cdot cdot cdot cdot cdot cdot cdot left( 1+frac { 1 }{ n } right) =left( n+1 right)
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 28NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 29

Ex 4.1 Class 11 Maths Question 15.
{ 1 }^{ 2 }+{ 3 }^{ 2 }+{ 5 }^{ 2 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ left( 2n-1 right) }^{ 2 }=frac { nleft( 2n-1 right) left( 2n+1 right) }{ 3 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : { 1 }^{ 2 }+{ 3 }^{ 2 }+{ 5 }^{ 2 }+cdot cdot cdot cdot cdot cdot cdot cdot +{ left( 2n-1 right) }^{ 2 }=frac { nleft( 2n-1 right) left( 2n+1 right) }{ 3 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 30NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 31

Ex 4.1 Class 11 Maths Question 16.
frac { 1 }{ 1.4 } +frac { 1 }{ 4.7 } +frac { 1 }{ 7.10 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 3n-2 right) left( 3n+1 right) } =frac { n }{ left( 3n+1 right) }
Solution.
Let the given statement be P(n), i.e.,
P(n) : frac { 1 }{ 1.4 } +frac { 1 }{ 4.7 } +frac { 1 }{ 7.10 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 3n-2 right) left( 3n+1 right) } =frac { n }{ left( 3n+1 right) }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 32NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 33

Ex 4.1 Class 11 Maths Question 17.
frac { 1 }{ 3.5 } +frac { 1 }{ 5.7 } +frac { 1 }{ 7.9 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 2n+1 right) left( 2n+3 right) } =frac { n }{ 3left( 2n+3 right) }
Solution.
Let the given statement be P(n), i.e.,
P(n) : frac { 1 }{ 3.5 } +frac { 1 }{ 5.7 } +frac { 1 }{ 7.9 } +cdot cdot cdot cdot cdot cdot cdot cdot +frac { 1 }{ left( 2n+1 right) left( 2n+3 right) } =frac { n }{ 3left( 2n+3 right) }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 34NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 35

Ex 4.1 Class 11 Maths Question 18.
1+2+3+cdot cdot cdot cdot cdot cdot cdot cdot +n<frac { 1 }{ 8 } { left( 2n+1 right) }^{ 2 }
Solution.
Let the given statement be P(n), i.e.,
P(n) : 1+2+3+cdot cdot cdot cdot cdot cdot cdot cdot +n<frac { 1 }{ 8 } { left( 2n+1 right) }^{ 2 }
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 36NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 37

Ex 4.1 Class 11 Maths Question 19.
n(n+1 )(n + 5) is a multiple of 3.
Solution.
Let the given statement be P(n), i.e.,
P(n): n(n + l)(n + 5) is a multiple of 3.
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 38NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 39

Ex 4.1 Class 11 Maths Question 20.
{ 10 }^{ 2n-1 }+1 is divisible by 11.
Solution.
Let the given statement be P(n), i.e.,
P(n): { 10 }^{ 2n-1 }+1 is divisible by 11
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 40

Ex 4.1 Class 11 Maths Question 21.
{ x }^{ 2n }-{ y }^{ 2n } is divisible by x + y.
Solution.
Let the given statement be P(n), i.e.,
P(n): { x }^{ 2n }-{ y }^{ 2n } is divisible by x + y.
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 41

Ex 4.1 Class 11 Maths Question 22.
{ 3 }^{ 2n+2 }-8n-9 is divisible by 8.
Solution.
Let the given statement be P(n), i.e.,
P(n): { 3 }^{ 2n+2 }-8n-9 is divisible by 8.
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 42

Ex 4.1 Class 11 Maths Question 23.
{ 41 }^{ n }-{ 14 }^{ n } is a multiple of 27.
Solution.
Let the given statement be P(n), i.e.,
P(n): { 41 }^{ n }-{ 14 }^{ n } is a multiple of 27.
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 43

Ex 4.1 Class 11 Maths Question 24.
left( 2n+7 right) <{ left( n+3 right) }^{ 2 }
Solution.
Let the given statement be P(n), i.e.,
P(n): left( 2n+7 right) <{ left( n+3 right) }^{ 2 }
First we prove that the statement is true for n = 1.
NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction 44

We hope the NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction help you. If you have any query regarding NCERT Solutions for Class 11 Maths Chapter 4 Principle of Mathematical Induction, drop a comment below and we will get back to you at the earliest.


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