integral of (x^5+3x)/(x^4+1)

解答

\int \frac{x ^{5} + 3 x}{x ^{4} + 1} d x

\frac{x ^{2}}{2} + arctan (x^{2}) + C

求解步骤

\int \frac{x ^{5} + 3 x}{x ^{4} + 1} d x

乘开

\frac{x ^{5} + 3 x}{x ^{4} + 1} : \frac{x ^{5}}{x ^{4} + 1} + \frac{3 x}{x ^{4} + 1}

使用积分加法定则:

\int f (x) \pm g (x) d x = \int f (x) d x \pm \int g (x) d x

= \int \frac{x ^{5}}{x ^{4} + 1} d x + \int \frac{3 x}{x ^{4} + 1} d x

\int \frac{x ^{5}}{x ^{4} + 1} d x = \frac{x ^{2}}{2} - \frac{1}{2} arctan (x^{2})

\int \frac{3 x}{x ^{4} + 1} d x = \frac{3}{2} arctan (x^{2})

= \frac{x ^{2}}{2} - \frac{1}{2} arctan (x^{2}) + \frac{3}{2} arctan (x^{2})

\int \frac{3 x}{( x + 5 ) ( 2 x - 1 )} d x

\int (- \frac{csc ( x ) cot ( x )}{6}) d x

\int \frac{x ^{2} + 7}{x} d x

\int x \cdot 1 0^{x} d x

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