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Let z be a complex number such that \left | z \right |+z=3+i (where i=\sqrt{-1}). The \left | z \right | is equal to :

  • Option 1)

    \frac{5}{3}

  • Option 2)

    \frac{\sqrt{41}}{4}

  • Option 3)

    \frac{5}{4}

  • Option 4)

    \frac{\sqrt{34}}{3}

Answers (1)

best_answer

 

Definition of Modulus of z(Complex Number) -

\left | z \right |=\sqrt{a^{2}+b^{2}} is the distance of z from origin in Argand plane

- wherein

Real part of z = Re (z) = a & Imaginary part of z = Im (z) = b

\left | z \right |+z=3+i

z=3-\left | z \right |+i.............(1)

Let \: a\: =3-\left | z \right |

=>\left | z \right |=3-a.................(2)

Now eqn ( 1 )

z=a+i

=>\left | z \right |=\sqrt{a^{2}+1}...............(3)

Using eqn ( 2 ) and ( 3 )

3-a=\sqrt{a^{2}+1}

(3-a)^{2}={a^{2}+1}

a=\frac{4}{3}

\left | z \right |=3-a=\frac{5}{3}

 


Option 1)

\frac{5}{3}

Option 2)

\frac{\sqrt{41}}{4}

Option 3)

\frac{5}{4}

Option 4)

\frac{\sqrt{34}}{3}

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