Q&A - Ask Doubts and Get Answers
Q

I have a doubt, kindly clarify. - Complex numbers and quadratic equations - JEE Main-5

Let z= \left ( a^{2}-4 \right )+\left ( a^{2}-3a+2 \right )i  , If \left | z \right |= 0  then 'a' equals \left ( Where \; a\, \epsilon \, R \right )

  • Option 1)

    -2

  • Option 2)

    -1

  • Option 3)

    0

  • Option 4)

    2

 
Answers (1)
115 Views

Since \left | z \right |=0 so z=0

it means a^{2}-4=0\: and \:also\: a^{2}-3a+2=0

a^{2}-4=0\: \Rightarrow \: a=2\: or\: -2

a^{2}-3a+2=0\: \Rightarrow a=1\: or\: 2

Both will hold when a = 2

\therefore Option (D)

 

Property of Modulus of z(Complex Number) -

|z|=0 iff z=0

- wherein

|z|= Modulus of z

 

 


Option 1)

-2

This is incorrect

Option 2)

-1

This is incorrect

Option 3)

0

This is incorrect

Option 4)

2

This is correct

Exams
Articles
Questions