CUET · MATHS · PYQ PAPER 2023
\((\vec{a} \cdot \hat{i})^2+(\vec{a} \cdot \hat{j})^2+(\vec{a} \cdot \hat{k})^2\) is equal to:
- A 1
- B \(\vec{a}\)
- C \(-\vec{a}\)
- D \(|\vec{a}|^2\)
Answer & Solution
Correct Answer
(D) \(|\vec{a}|^2\)
Step-by-step Solution
Detailed explanation
\(\vec{a} = a_x \hat{i} + a_y \hat{j} + a_z \hat{k}\) \((\vec{a} \cdot \hat{i})^2+(\vec{a} \cdot \hat{j})^2+(\vec{a} \cdot \hat{k})^2 = (a_x)^2 + (a_y)^2 + (a_z)^2\) \(= |\vec{a}|^2\)
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