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4-1.Complex numbers
medium
$({x^4} + 2xi) - (3{x^2} + yi) = $$(3 - 5i) + (1 + 2yi)$ નું સમાધાન કરે તેવી $x$ અને $y$ ની વાસ્તવિક કિમત મેળવો.
A
$x = 2,y = 3$
B
$x = - 2,y = \frac{1}{3}$
C
બંને $ (a)$ અને $(b)$
D
એકપણ નહીં.
Solution
(c) Given equation
$({x^4} + 2xi) – (3{x^2} + yi) = (3 – 5i) + (1 + 2yi)$
$ \Rightarrow \,\,\,({x^4} – 3{x^2}) + i(2x – 3y) = 4 – 5i$
Equating real and imaginary parts, we get
${x^4} – 3{x^2} = 4$ ……$(i)$
and $2x – 3y = – 5$ …..$(ii)$
From $ (i)$ and $ (ii)$, we get $x = \pm 2$and $y = 3,\frac{1}{3}$
Trick : Put $x = 2,y = 3$and then $x = – 2,$$y = \frac{1}{3},$ we see that they both satisfy the given equation.
Standard 11
Mathematics