Question

Simplify $\sum _{n=1}^3\frac{n}{n^4+4}$.

• A. $0.2773$
• B. $0.3753$
• C. $0.3353$
• D. $0.2573$

Answer 1

Answer: (C)

$0.3353$

We have,

$\sum _{n=1}^3\frac{n}{n^4+4}$

$\Rightarrow \frac{1}{1^4+4}+\frac{2}{2^4+4}+\frac{3}{3^4+4}$

$\Rightarrow \frac{1}{1+4}+\frac{2}{16+4}+\frac{3}{81+4}$

$\Rightarrow \frac{1}{5}+\frac{2}{20}+\frac{3}{85}$

$\Rightarrow 0.2+0.1+0.0353$

$\Rightarrow 0.3353$

Hence, this is the answer.