$cos(\overrightarrow{u},\overrightarrow{v})=\frac{(-4)\times (-1)+(-3)\times (-7)}{\sqrt{(-4)^{2}+(-3)^{2}}\times \sqrt{(-1)^{2}+(-7)^{2}}}=\frac{25}{\sqrt{25}\times \sqrt{50}}=\frac{1}{\sqrt{2}}$
Suy ra $(\overrightarrow{u},\overrightarrow{v})=45^{\circ}$
Đáp án: C