1.

If α and β are the roots of the quadratic equation ax2 + bx + c = 0, such that β = α1/3, then(a) (a3b)1/4 + (ac3)1/4 + a = 0(b) (a3c)1/4 + (ac3)1/4 + b = 0(c) (a3b)1/4 + (ab3)1/4 + c = 0(d) (a3c)1/4 + (bc3)1/4 + a = 0

Answer»

(b) (ac3)1/4 + (a3c)1/4 + b = 0

Let α, β be the roots of the equation ax2 + bx + c = 0. Then,

α + β = \(-\frac{b}{a}\)                     .....(i)

αβ = \(\frac{c}{a}\)                            ......(ii)

and   β = α1/3                .......(iii)

∴ From (ii) and (iii), α. (α)1/3 \(\frac{c}{a}\) ⇒ α4/3 \(\frac{c}{a}\) ⇒ α = \(\bigg(\frac{c}{a}\bigg)^{3/4}\)

∴ β = \(\bigg(\big(\frac{c}{a}\big)^{3/4}\bigg)^{1/3}\) = \(\bigg(\frac{c}{a}\bigg)^{1/4}\)

∴ Putting these values of a and b in eqn. (i), we have

\(\bigg(\frac{c}{a}\bigg)^{3/4}\) + (c/a)1/4\(-\frac{b}{a}\)

⇒ a. a–3/4 c3/4 + a. a–1/4 c1/4 = – b 

⇒ a1/4 c3/4 + a3/4 c1/4 + b = 0 

(ac3)1/4 + (a3c)1/4 + b = 0.



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