integral of 3/((x-2)(x^2+4))

Lösung

\int \frac{3}{( x - 2 ) ( x ^{2} + 4 )} d x

\frac{3}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln \frac{x ^{2}}{4} + 1 - arctan (\frac{x}{2}))) + C

Schritte zur Lösung

\int \frac{3}{( x - 2 ) ( x ^{2} + 4 )} d x

Entferne die Konstante:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

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

Wende integrale Substitution an

= 3 \cdot \int \frac{1}{4 ( u - 1 ) ( u ^{2} + 1 )} d u

Entferne die Konstante:

\int a \cdot f (x) d x = a \cdot \int f (x) d x

= 3 \cdot \frac{1}{4} \cdot \int \frac{1}{( u - 1 ) ( u ^{2} + 1 )} d u

Ermittle den Partialbruch von

\frac{1}{( u - 1 ) ( u ^{2} + 1 )} : \frac{1}{2 ( u - 1 )} + \frac{- u - 1}{2 ( u ^{2} + 1 )}

= 3 \cdot \frac{1}{4} \cdot \int \frac{1}{2 ( u - 1 )} + \frac{- u - 1}{2 ( u ^{2} + 1 )} d u

Wende die Summenregel an:

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

= 3 \cdot \frac{1}{4} (\int \frac{1}{2 ( u - 1 )} d u + \int \frac{- u - 1}{2 ( u ^{2} + 1 )} d u)

\int \frac{1}{2 ( u - 1 )} d u = \frac{1}{2} ln ∣ u - 1 ∣

\int \frac{- u - 1}{2 ( u ^{2} + 1 )} d u = \frac{1}{2} (- \frac{1}{2} ln u^{2} + 1 - arctan (u))

= 3 \cdot \frac{1}{4} (\frac{1}{2} ln ∣ u - 1 ∣ + \frac{1}{2} (- \frac{1}{2} ln u^{2} + 1 - arctan (u)))

Setze in

u = \frac{x}{2}

ein

= 3 \cdot \frac{1}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln (\frac{x}{2})^{2} + 1 - arctan (\frac{x}{2})))

Vereinfache

3 \cdot \frac{1}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln (\frac{x}{2})^{2} + 1 - arctan (\frac{x}{2}))) : \frac{3}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln \frac{x ^{2}}{4} + 1 - arctan (\frac{x}{2})))

= \frac{3}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln \frac{x ^{2}}{4} + 1 - arctan (\frac{x}{2})))

Füge eine Konstante zur Lösung hinzu

= \frac{3}{4} (\frac{1}{2} ln \frac{x}{2} - 1 + \frac{1}{2} (- \frac{1}{2} ln \frac{x ^{2}}{4} + 1 - arctan (\frac{x}{2}))) + C

\frac{d}{d x} (\frac{3 x}{1 - x})

\int \frac{( x ^{\frac{1}{3}} )}{x ^{\frac{2}{3}}} d x

\int \frac{1}{( 8 - 2 x - x ^{2} ) ^{\frac{3}{2}}} d x

n = 0 \sum \infty \frac{2 ^{n}}{4 ^{n}}

\int (4 x^{2} - 5 x)^{5} (8 x - 5) d x