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$$$\frac{1}{2}\cdot \left\langle 2 \cos{\left(t \right)}, - 2 \sin{\left(t \right)}, 0\right\rangle$$$
Votre saisie
Calculer $$$\frac{1}{2}\cdot \left\langle 2 \cos{\left(t \right)}, - 2 \sin{\left(t \right)}, 0\right\rangle$$$.
Solution
Multipliez chaque coordonnée du vecteur par le scalaire :
$$${\color{OrangeRed}\left(\frac{1}{2}\right)}\cdot \left\langle 2 \cos{\left(t \right)}, - 2 \sin{\left(t \right)}, 0\right\rangle = \left\langle {\color{OrangeRed}\left(\frac{1}{2}\right)}\cdot \left(2 \cos{\left(t \right)}\right), {\color{OrangeRed}\left(\frac{1}{2}\right)}\cdot \left(- 2 \sin{\left(t \right)}\right), {\color{OrangeRed}\left(\frac{1}{2}\right)}\cdot \left(0\right)\right\rangle = \left\langle \cos{\left(t \right)}, - \sin{\left(t \right)}, 0\right\rangle$$$
Réponse
$$$\frac{1}{2}\cdot \left\langle 2 \cos{\left(t \right)}, - 2 \sin{\left(t \right)}, 0\right\rangle = \left\langle \cos{\left(t \right)}, - \sin{\left(t \right)}, 0\right\rangle$$$A