Question

Only talented students can click this question

Answer 1

the answer is 9 n/ n+1

Answer 2

Option (B) is the right answer. I don't know how option (B) is the answer but I compared the options by the sum and it seems that option (B) is correct.

Let's check.

$\frac{3}{1^2} = 3 \\ \\ \frac{6 \times 1}{1 + 1} = \frac{6}{2} = 3 \\ \\ \\ \frac{3}{1^2} + \frac{5}{1^2 + 2^2} = 3 + 1 = 4 \\ \\ \frac{6 \times 2}{2 + 1} = \frac{12}{3} = 4 \\ \\ \\ \frac{3}{1^2} + \frac{5}{1^2 + 2^2} + \frac{7}{1^2 + 2^2 + 3^2} = 3 + 1 + \frac{1}{2} = 4\frac{1}{2} \\ \\ \frac{6 \times 3}{3 + 1} = \frac{18}{4} = 4\frac{1}{2}$

So option (B) is correct.