JEE Mains · Maths · STD 12 - 10. vector algebra
Let \(\vec a\) and \(\vec b\) be two unit vectors such that \(\left| {\vec a\, + \,\vec b} \right| = \sqrt 3 .\) If \(\vec c = \vec a\, + \,2\vec b + 3\,(\vec a \times \vec b),\) then \(2\left| {\vec c} \right|\) is equal to
- A \(\sqrt {55}\)
- B \(\sqrt {37}\)
- C \(\sqrt {51}\)
- D \(\sqrt {43}\)
Answer & Solution
Correct Answer
(A) \(\sqrt {55}\)
Step-by-step Solution
Detailed explanation
\(\left| {\vec a + \vec b} \right| = \sqrt 3 \) angle between \(\overrightarrow{\mathrm{a}}\) and \(\overrightarrow{\mathrm{b}}\) is \(60^{\circ} .\) \(\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{b}}\) is \(\perp^{\mathrm{r}}\) to plane containing…
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