Question:
Find the angle between the line $\overrightarrow{\mathrm{r}}=(3 \hat{\mathrm{i}}+\hat{\mathrm{k}})+\lambda(\hat{\mathrm{j}}+\hat{\mathrm{k}})$ and the plane $\overrightarrow{\mathrm{r}} \cdot(2 \hat{\mathrm{i}}-\hat{\mathrm{j}}+2 \hat{\mathrm{k}})=1$.
Solution:
