Class 11 NCERT Solutions- Chapter 5 Complex Numbers And Quadratic Equations – Exercise 5.1 | Set 2

Chapter 5 Complex Numbers And Quadratic Equations – Exercise 5.1 | Set 1

For Q.11 to Q.13 find the multiplicative inverse of the given number 

Question 11. 4-3i

Solution:

Let’s denote given number as a,

the complement of a =  = 

 = (4+3i)

Modulus of a = (|a|) = √((4)²+(3)²)

|a|= √(16+9)=√(25)

|a| = 5

 = 

 = 

Question 12. √5+3i

Solution:

Let’s denote given number as a,

the complement of a = 

 = √5-3i

Modulus of a (|a|) = √((√5)²+(-3)²)

|a|= √(5+9)=√(14)

|a|=√(14)

Question 13. -i

Solution:

Let’s denote given number as a,

the complement of a = 

 = i

Modulus of a (|a|) = √((0)²+(-1)²)

|a|= √(1)

|a|=1

 = i

Express the following expression in form of a+ib

Question 14.

Solution:

Let’s denote the given expression as z,

z = 

z = 

z = 

As we know that (a+b)(a-b) = a² – b²

z = 

z = 

z = 

z = 

z = 

As we can write  = -i

z = 

z = 0-