33. The vector $\vec{r}$ forms angles of $60^{\circ}$ with the $O x$ and $O y$ axes. What angle does this vector form with the $O z$ axis?
33. According to the formula obtained in the previous problem, we have:

$$
\cos ^{2} 60^{\circ}+\cos ^{2} 60^{\circ}+\cos ^{2} \gamma=1
$$

or

$$
\begin{gathered}
\frac{1}{4}+\frac{1}{4}+\cos ^{2} \gamma=1, \cos ^{2} \gamma=\frac{1}{2} \\
\cos \gamma= \pm \frac{\sqrt{2}}{2}, \gamma=45^{\circ} \text { or } \gamma=135^{\circ} .
\end{gathered}
$$