Question:
Find the angle between $\overrightarrow{\mathrm{a}}$ and $\overrightarrow{\mathrm{b}}$, when
i. $|\overrightarrow{\mathrm{a}}|=2,|\overrightarrow{\mathrm{b}}|=1$ and $\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{b}}=\sqrt{3}$
ii. $|\overrightarrow{\mathrm{a}}|=|\overrightarrow{\mathrm{b}}|=\sqrt{2}$ and $\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{b}}=-1$
Solution:
