If {z₁} = 1 - i and {z₂} = - 2 + 4i , then {mathop{rm Im}nolimits} left( {frac{{{z₁}{z₂}}}{{

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4-1.Complex numbers

easy

If ${z_1} = 1 - i$ and ${z_2} = - 2 + 4i$, then ${\mathop{\rm Im}\nolimits} \left( {\frac{{{z_1}{z_2}}}{{{z_1}}}} \right) = $

A

$1$

B

$2$

C

$3$

D

$4$

Solution

(d) If ${z_1} = 1 – i$and ${z_2} = – 2 + 4i$
Then $\frac{{{z_1}{z_2}}}{{{z_1}}} = \frac{{(1 – i)( – 2 + 4i)}}{{1 – i}} = – 2 + 4i$

==> ${\mathop{\rm Im}\nolimits} \left( {\frac{{{z_1}{z_2}}}{{{z_1}}}} \right) = 4$.

Standard 11

Mathematics

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