CBSE BoardEnglish MediumSTD 11 ScienceMathsComplex Numbers and Quadratic Equations1 Mark
MCQ
If $a + ib = c + id,$ then:
A
$a^2 + c^2 = 0$
B
$b^2 + c^2 = 0$
C
$b^2+ d^2 = 0$
✓
$a^2 + b^2 = c^2 + d^2$
✓
Answer
Correct option: D.
$a^2 + b^2 = c^2 + d^2$
$a^2 + b^2 = c^2 + d^2$
Given that $\text{a}+\text{ib}=\text{c}+\text{id}$
$\Rightarrow|\text{a}+\text{ib}|=|\text{c}+\text{id}|$
$\Rightarrow\sqrt{\text{a}^2+\text{b}^2}$
$=\sqrt{\text{c}^2+\text{d}^2}$
Squaring both sides$,$ we get ${a^2 + b^2 = c^2 + d^2}$
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