integral of 1/(7x-x^2)

Lösung

\int \frac{1}{7 x - x ^{2}} d x

\frac{1}{7} (ln (\frac{2}{7} ∣ x ∣) - ln \frac{2}{7} x - 2) + C

Schritte zur Lösung

\int \frac{1}{7 x - x ^{2}} d x

Vervollständige das Quadrat

7 x - x^{2} : - (x - \frac{7}{2})^{2} + \frac{49}{4}

= \int \frac{1}{- ( x - \frac{7}{2} ) ^{2} + \frac{49}{4}} d x

Wende U-Substitution an

= \int \frac{4}{- 4 u ^{2} + 49} d u

Entferne die Konstante:

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

= 4 \cdot \int \frac{1}{- 4 u ^{2} + 49} d u

Wende integrale Substitution an

= 4 \cdot \int \frac{1}{14 ( - v ^{2} + 1 )} d v

Entferne die Konstante:

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

= 4 \cdot \frac{1}{14} \cdot \int \frac{1}{- v ^{2} + 1} d v

Nutze das gemeinsame Integral :

\int \frac{1}{- v ^{2} + 1} d v = \frac{ln ∣ v + 1 ∣}{2} - \frac{ln ∣ v - 1 ∣}{2}

= 4 \cdot \frac{1}{14} (\frac{ln ∣ v + 1 ∣}{2} - \frac{ln ∣ v - 1 ∣}{2})

Ersetze zurück

= 4 \cdot \frac{1}{14} (\frac{ln \frac{2}{7} ( x - \frac{7}{2} ) + 1}{2} - \frac{ln \frac{2}{7} ( x - \frac{7}{2} ) - 1}{2})

Vereinfache

4 \cdot \frac{1}{14} (\frac{ln \frac{2}{7} ( x - \frac{7}{2} ) + 1}{2} - \frac{ln \frac{2}{7} ( x - \frac{7}{2} ) - 1}{2}) : \frac{1}{7} (ln (\frac{2}{7} ∣ x ∣) - ln \frac{2}{7} x - 2)

= \frac{1}{7} (ln (\frac{2}{7} ∣ x ∣) - ln \frac{2}{7} x - 2)

Füge eine Konstante zur Lösung hinzu

= \frac{1}{7} (ln (\frac{2}{7} ∣ x ∣) - ln \frac{2}{7} x - 2) + C

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