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JEE Mains · Maths · STD 12 - 10. vector algebra

Let \(\vec{a}=\hat{i}+2 \hat{j}+\hat{k}, \vec{b}=3 \hat{i}-3 \hat{j}+3 \hat{k}\), \(\overrightarrow{\mathrm{c}}=2 \hat{\mathrm{i}}-\hat{\mathrm{j}}+2 \hat{\mathrm{k}}\) and \(\overrightarrow{\mathrm{d}}\) be a vector such that \(\overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{d}}=\overrightarrow{\mathrm{c}} \times \overrightarrow{\mathrm{d}}\) and \(\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{d}}=4\). Then \(|(\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{d}})|^2\) is equal to ______ .

  1. A 120
  2. B 124
  3. C 128
  4. D 132
Verified Solution

Answer & Solution

Correct Answer

(C) 128

Step-by-step Solution

Detailed explanation

\begin{aligned} & \overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{d}}=\overrightarrow{\mathrm{c}} \times \overrightarrow{\mathrm{d}} \text {-and } \overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{d}}=4 \\ & \Rightarrow…