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Let z= -12-5i and w= 2\sqrt{11}+iy  such that z and w both are equidistant from origin then y equals \left ( Where\; y\epsilon R \right )

  • Option 1)

    2\sqrt{5}

  • Option 2)

    3\sqrt{5}

  • Option 3)

    4\sqrt{5}

  • Option 4)

    5\sqrt{5}

 

Answers (1)

\because z & w are equidistant from origin so \left |z \right |=\left | w \right |

\Rightarrow \: \sqrt{144+25}=\sqrt{44+y^{2}}

\Rightarrow \: \sqrt{169}=\sqrt{44+y^{2}}

\Rightarrow \: 169=44+y^{2}

\Rightarrow \: y^{2}=125

\Rightarrow \: y=\pm 5\sqrt{5}

\therefore Option (D)

 

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

 

 


Option 1)

2\sqrt{5}

This is incorrect

Option 2)

3\sqrt{5}

This is incorrect

Option 3)

4\sqrt{5}

This is incorrect

Option 4)

5\sqrt{5}

This is correct

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