BD Merit - Freelancing, BCS, Bank, Primary, Admission, NTRCA

Discuss Forum

1. $a^{4} - 51 a^{2} + 1 = 0$

Answer: Option B

Explanation:

দেওয়া আছে, a^{4} - 51 a^{2} + 1 = 0 \Rightarrow a^{4} + 1 = 51 a^{2} \Rightarrow \frac{a^{4} + 1}{a^{2}} = \frac{51 a^{2}}{a^{2}} \Rightarrow \frac{a^{4}}{a^{2}} + \frac{1}{a^{2}} = 51 \Rightarrow a^{2} + \frac{1}{a^{2}} = 51 এখন, {(a - \frac{1}{a})}^{2} = {(a + \frac{1}{a})}^{2} - 4 . a . \frac{1}{a} = a^{2} + 2 . a . \frac{1}{a} + \frac{1}{a^{2}} - 4 = a^{2} + \frac{1}{a^{2}} - 2 = 51 - 2 = 49 ∴ a - \frac{1}{a} = \sqrt{49} = \pm 7

Post your comments here:

Name:

Mobile:

Email:(Optional)

» Your comments will be displayed only after manual approval.