Question:
If $\vec{a}=(2 \hat{i}+2 \hat{j}+3 \hat{k}), \vec{b}=(-\hat{i}+2 \hat{j}+\hat{k})$ and $\overrightarrow{\mathrm{c}}=(3 \hat{\mathrm{i}}+\hat{\mathrm{j}})$ are such that $(\vec{a}+\lambda \vec{b})$ is perpendicular to $\vec{C}$ then find the value of $\lambda$.
Solution: