integral from 0 to pi/4 of (cos(x))^2

Lösung

\int_{0}^{\frac{π}{4}} (cos (x))^{2} d x

\frac{π + 2}{8}

Dezimale

0.64269 \dots

Schritte zur Lösung

\int_{0}^{\frac{π}{4}} (cos (x))^{2} d x

Vereinfache

= \int_{0}^{\frac{π}{4}} cos^{2} (x) d x

Umschreiben mit Hilfe von Trigonometrie-Identitäten

= \int_{0}^{\frac{π}{4}} \frac{1 + cos ( 2 x )}{2} d x

Entferne die Konstante:

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

= \frac{1}{2} \cdot \int_{0}^{\frac{π}{4}} 1 + cos (2 x) d x

Wende die Summenregel an:

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

= \frac{1}{2} (\int_{0}^{\frac{π}{4}} 1 d x + \int_{0}^{\frac{π}{4}} cos (2 x) d x)

\int_{0}^{\frac{π}{4}} 1 d x = \frac{π}{4}

\int_{0}^{\frac{π}{4}} cos (2 x) d x = \frac{1}{2}

= \frac{1}{2} (\frac{π}{4} + \frac{1}{2})

Vereinfache

\frac{1}{2} (\frac{π}{4} + \frac{1}{2}) : \frac{π + 2}{8}

= \frac{π + 2}{8}

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