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AP EAMCET · Maths · Vector Algebra

Given three vectors \(\mathbf{a}=2 \hat{\mathbf{i}}-\hat{\mathbf{j}}+\hat{\mathbf{k}}, \mathbf{b}=\hat{\mathbf{i}}+2 \hat{\mathbf{j}}-\hat{\mathbf{k}}\) and \(\mathbf{c}=\hat{\mathbf{i}}+\hat{\mathbf{j}}-2 \hat{\mathbf{k}}\), a vector in the plane of \(\mathbf{b}\) and \(\mathbf{c}\) whose projection on \(\mathbf{a}\) is of magnitude \(\sqrt{\frac{2}{3}}\) is

  1. A \(-2 \hat{\mathbf{i}}-\hat{\mathbf{j}}+5 \hat{\mathbf{k}}\)
  2. B \(2 \hat{\mathbf{i}}+3 \hat{\mathbf{j}}+3 \hat{\mathbf{k}}\)
  3. C \(2 \hat{\mathbf{i}}+\hat{\mathbf{j}}+5 \hat{\mathbf{k}}\)
  4. D \(2 \hat{\mathbf{i}}-3 \hat{\mathbf{j}}+3 \hat{\mathbf{k}}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(-2 \hat{\mathbf{i}}-\hat{\mathbf{j}}+5 \hat{\mathbf{k}}\)

Step-by-step Solution

Detailed explanation

Given three vectors are \(\begin{aligned} \mathbf{a} & =2 \hat{\mathbf{i}}-\hat{\mathbf{j}}+\hat{\mathbf{k}}, \mathbf{b}=\hat{\mathbf{i}}+2 \hat{\mathbf{j}}-\hat{\mathbf{k}} \\ \text {and } \quad \mathbf{c} & =\hat{\mathbf{i}}+\hat{\mathbf{j}}-2 \hat{\mathbf{k}} \end{aligned}\)…