Sequences and Series 3 Question 8
8. Let $f(x)=a x^{2}+b x+c, a \neq 0$ and $\Delta=b^{2}-4 a c$. If $\alpha+\beta$, $\alpha^{2}+\beta^{2}$ and $\alpha^{3}+\beta^{3}$ are in GP, then
(a) $\Delta \neq 0$
(b) $b \Delta=0$
(c) $c \Delta=0$
(d) $b c \neq 0$
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Answer:
Correct Answer: 8. (c)
Solution:
- Since, $(\alpha+\beta),\left(\alpha^{2}+\beta^{2}\right),\left(\alpha^{3}+\beta^{3}\right)$ are in GP.
