CBSE 2023 · Region 3 · Set 1 · Q13 · 1 mark

The value of $\displaystyle \lambda$ for which the angle between the lines $\displaystyle \vec{\mathrm{r}}=\hat{\mathrm{i}}+\hat{\mathrm{j}}+\hat{\mathrm{k}}+p(2 \hat{\mathrm{i}}+\hat{\mathrm{j}}+2 \hat{\mathrm{k}})$ and $\displaystyle \overrightarrow{\mathrm{r}}=(1+\mathrm{q}) \hat{\mathrm{i}}+(1+\mathrm{q} \lambda) \hat{\mathrm{j}}+(1+\mathrm{q}) \hat{\mathrm{k}}$ is $\displaystyle \frac{\pi}{2}$ is :

CBSE Class 12 Mathematics past-paper question from the 2023board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.