JEE Mains · Maths · STD 12 - 10. vector algebra
Let \(\hat{a}\) and \(\hat{b}\) be two unit vectors such that \(|(\hat{ a }+\hat{ b })+2(\hat{ a } \times \hat{ b })|=2\). If \(\theta \in(0, \pi)\) is the angle between \(\hat{a}\) અને \(\hat{b}\), then among the statements : \(( S_{1})\): \(2|\hat{ a } \times \hat{ b }|=|\hat{ a }-\hat{ b }|\) \((S_{2})\) : The projection of \(\hat{a}\) on \((\hat{a}+\hat{b})\) is \(\frac{1}{2}\)
- A Only \((S_{1})\) is true
- B Only \((S_{2})\) is true
- C Both \((S_{1})\) and \((S_{2})\) are true
- D Both \((S_{1})\) and \((S_{2})\) are false
Answer & Solution
Correct Answer
(C) Both \((S_{1})\) and \((S_{2})\) are true
Step-by-step Solution
Detailed explanation
\(|(\hat{a}+\hat{b})+2(\hat{a} \times \hat{b})|=2, \theta \in(0, \pi)\) \(((\hat{a}+\hat{b})+2(\hat{a} \times \hat{b})) \cdot((\hat{a}+\hat{b})+2(\hat{a} \times \hat{b}))=4\) \(|\hat{a}+\hat{b}|^{2}+4|(\hat{a} \times \hat{b})|^{2}+0=4\) Let the angle be \(\theta\) between…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- The sum of possible values of \(x\) for \(\tan ^{-1}( x +1)+\cot ^{-1}\left(\frac{1}{ x -1}\right)=\tan ^{-1}\left(\frac{8}{31}\right)\) isJEE Mains 2021 Hard
- The number of solutions of \(\sin ^2 \mathrm{x}+\left(2+2 \mathrm{x}-\mathrm{x}^2\right) \sin \mathrm{x}-3(\mathrm{x}-1)^2=0\), where \(-\pi \leq \mathrm{x} \leq \pi\), is ..........JEE Mains 2024 Hard
- Let \(\alpha\) be a root of the equation \(1+x^{2}+x^{4}=0\). Then the value of \(\alpha^{1011}+\alpha^{\text {2022 }}-\alpha^{\text {3033}}\) is equal toJEE Mains 2022 Medium
- If all the words, with or without meaning, are written using the letters of the word \(QUEEN\) and are arranged as in English dictionary, then the position of the word \(QUEEN\) isJEE Mains 2017 Hard
- If \(y = y ( x )\) is the solution of the differential equation \(\frac{ dy }{ dx }+(\tan x ) y =\sin x , 0 \leq x \leq \frac{\pi}{3},\) with \(y (0)=0,\) then \(y \left(\frac{\pi}{4}\right)\) equal to :JEE Mains 2021 Hard
- The largest value of \( n \), for which \(40^{ n }\) divides 60!, isJEE Mains 2026 Easy
More PYQs from JEE Mains
- Let the lines \(3 x-4 y-\alpha=0,8 x-11 y-33=0\), and \(2 x-3 y+\lambda=0\) be concurrent. If the image of the point
\((1,2)\) in the line \(2 x-3 y+\lambda=0\) is \(\left(\frac{57}{13}, \frac{-40}{13}\right)\), then \(|\alpha \lambda|\) is equal toJEE Mains 2025 Medium - If \(m\) is the slope of a common tangent to the curves \(\frac{x^{2}}{16}+\frac{y^{2}}{9}=1\) and \(x^{2}+y^{2}=12\), then \(12\; m ^{2}\) is equal toJEE Mains 2022 Hard
- If \(0 \le x \le \pi \) and \({81^{{{\sin }^2}x}} + {81^{{{\cos }^2}x}} = 30\), then \(x =\)JEE Mains 2021 Hard
- Let \(p\) and \(q\) be two positive numbers such that \(p + q =2\) and \(p ^{4}+ q ^{4}=272 .\) Then \(p\) and \(q\) are roots of the equationJEE Mains 2021 Hard
- Let the vertex \(A\) of a triangle \(ABC\) be \((1, 2)\), and the mid-point of the side \(AB\) be \((5, -1)\). If the centroid of this triangle is \((3, 4)\) and its circumcenter is \((\alpha, \beta)\), then \(21(\alpha + \beta)\) is equal to:JEE Mains 2026 Medium
- The number of real solutions of the equation \(e ^{4 x }+4 e ^{3 x }-58 e ^{2 x }+4 e ^{ x }+1=0\) is..........JEE Mains 2022 Hard