Find \(\int \frac{x^{3} + 5x + 1}{x^{3}} \mathrm {d} x\)

A.

\(x^{2} + 10x + c\)

B.

\(x + \frac{5}{3}x^{3} + x^{4} + c\)

C.

\(x - 5x^{2} - 2x^{3} + c\)

D.

\(x - \frac{5}{x} - \frac{1}{2x^{2}} + c\)

Correct answer is D

\(\frac{x^{3} + 5x + 1}{x^{3}} \equiv  1 + \frac{5}{x^{2}} + \frac{1}{x^{3}}\)

\(\equiv \int (1 + \frac{5}{x^{2}} + \frac{1}{x^{3}}) \mathrm {d} x = \int (1 + 5x^{-2} + x^{-3}) \mathrm {d} x\)

= \((x - 5x^{-1} - \frac{1}{2}x^{-2} + c)\)

= \(x - \frac{5}{x} - \frac{1}{2x^{2}} + c\).