JEE Mains · Maths · STD 12 - 10. vector algebra
If \(\vec{a}\) and \(\vec{b}\) are two vectors such that \(|\vec{a}| = 2\) and \(|\vec{b}| = 3\), then the maximum value of \(3\left|\left(3\vec{a} + 2\vec{b}\right)\right| + 4\left|\left(3\vec{a} - 2\vec{b}\right)\right|\) is :
- A \(30\)
- B \(36\)
- C \(60\)
- D \(72\)
Answer & Solution
Correct Answer
(C) \(60\)
Step-by-step Solution
Detailed explanation
Let \(\theta\) be the angle between \(\vec{a}\) and \(\vec{b}\). We have \(|3\vec{a} + 2\vec{b}| = \sqrt{9|\vec{a}|^2 + 4|\vec{b}|^2 + 12|\vec{a}||\vec{b}|\cos\theta}\) Substituting \(|\vec{a}| = 2\) and \(|\vec{b}| = 3\):…
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