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MHT CET · Maths · Vector Algebra

If \(\overline{\mathrm{p}}=2 \hat{i}+\hat{\mathrm{k}}, \quad \overline{\mathrm{q}}=\hat{i}+\hat{\mathrm{j}}+\hat{\mathrm{k}}, \quad \overline{\mathrm{r}}=4 \hat{i}-3 \hat{\mathrm{j}}+7 \hat{\mathrm{k}}\) and a vector \(\overline{\mathrm{m}}\) is such that \(\overline{\mathrm{m}} \times \overline{\mathrm{q}}=\overline{\mathrm{r}} \times \overline{\mathrm{q}}, \overline{\mathrm{m}} \cdot \overline{\mathrm{p}}=0\), then \(\overline{\mathrm{m}}=\ldots\).

  1. A \(\hat{i}-8 \hat{j}-2 \hat{k}\)
  2. B \(-10 \hat{i}+3 \hat{j}+7 \hat{k}\)
  3. C \(-\hat{i}-8 \hat{j}+2 \hat{k}\)
  4. D \(2 \hat{i}+4 \hat{j}+\hat{k}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(-\hat{i}-8 \hat{j}+2 \hat{k}\)

Step-by-step Solution

Detailed explanation

\((\overline{\mathrm{m}} - \overline{\mathrm{r}}) \times \overline{\mathrm{q}} = \overline{0} \implies \overline{\mathrm{m}} = \overline{\mathrm{r}} + \lambda \overline{\mathrm{q}}\) \(\overline{\mathrm{m}} = (4 \hat{i}-3 \hat{\mathrm{j}}+7 \hat{\mathrm{k}}) + \lambda (\hat{i}+\hat{\mathrm{j}}+\hat{\mathrm{k}}) = (4+\lambda) \hat{i} + (-3+\lambda) \hat{\mathrm{j}} + (7+\lambda) \hat{\mathrm{k}}\)