Lösung Winkel berechnen

Zuletzt geändert von Daniel Stocker am 2024/02/05 17:12

a) $cos(\alpha) = \frac{\vec a \cdot \vec b}{\mid\vec a \mid \cdot \mid \vec b \mid} = \frac{7\cdot (-1)+5\cdot 2 + (-3) \cdot (-2) }{\sqrt{7^2+5^2+(-3)^2}\cdot \sqrt{(-1)^2+2^2+(-2)^2}} = \frac{9}{\sqrt{83} \cdot 3} = \frac{3}{\sqrt{83}}$
$\Rightarrow \alpha \approx 70,77^{\circ}$

b) $cos(\alpha) = \frac{\vec a \cdot \vec c}{\mid\vec a \mid \cdot \mid \vec c \mid} = \frac{7\cdot 1,5+5\cdot 2,1 + (-3) \cdot 7 }{\mid\vec a \mid \cdot \mid \vec c \mid} = \frac{0}{\mid\vec a \mid \cdot \mid \vec c \mid} = 0$
$\Rightarrow \alpha = 90^{\circ}$