1
JEE Main 2023 (Online) 12th April Morning Shift
+4
-1
Out of Syllabus

Let $$a, b, c$$ be three distinct real numbers, none equal to one. If the vectors $$a \hat{i}+\hat{\mathrm{j}}+\hat{\mathrm{k}}, \hat{\mathrm{i}}+b \hat{j}+\hat{\mathrm{k}}$$ and $$\hat{\mathrm{i}}+\hat{\mathrm{j}}+c \hat{\mathrm{k}}$$ are coplanar, then $$\frac{1}{1-a}+\frac{1}{1-b}+\frac{1}{1-c}$$ is equal to :

A
$$-$$2
B
1
C
$$-$$1
D
2
2
JEE Main 2023 (Online) 12th April Morning Shift
+4
-1
Out of Syllabus

Let $$\lambda \in \mathbb{Z}, \vec{a}=\lambda \hat{i}+\hat{j}-\hat{k}$$ and $$\vec{b}=3 \hat{i}-\hat{j}+2 \hat{k}$$. Let $$\vec{c}$$ be a vector such that $$(\vec{a}+\vec{b}+\vec{c}) \times \vec{c}=\overrightarrow{0}, \vec{a} \cdot \vec{c}=-17$$ and $$\vec{b} \cdot \vec{c}=-20$$. Then $$|\vec{c} \times(\lambda \hat{i}+\hat{j}+\hat{k})|^{2}$$ is equal to :

A
53
B
62
C
49
D
46
3
JEE Main 2023 (Online) 11th April Evening Shift
+4
-1
Out of Syllabus

If four distinct points with position vectors $$\vec{a}, \vec{b}, \vec{c}$$ and $$\vec{d}$$ are coplanar, then $$[\vec{a} \,\,\vec{b} \,\,\vec{c}]$$ is equal to :

A
$$[\vec{d} \,\,\,\,\,\vec{b} \,\,\,\,\,\vec{a}]+[\vec{a} \,\,\,\,\,\vec{c} \,\,\,\,\,\vec{d}]+[\vec{d} \,\,\,\,\,\vec{b} \,\,\,\,\,\vec{c}]$$
B
$$[\vec{b} \,\,\,\,\,\vec{c} \,\,\,\,\,\vec{d}]+[\vec{d} \,\,\,\,\,\vec{a} \,\,\,\,\,\vec{c}]+[\vec{d} \,\,\,\,\,\vec{b} \,\,\,\,\,\vec{a}]$$
C
$$[\vec{a} \,\,\,\,\,\vec{d} \,\,\,\,\,\vec{b}]+[\vec{d} \,\,\,\,\,\vec{c} \,\,\,\,\,\vec{a}]+[\vec{d} \,\,\,\,\,\vec{b} \,\,\,\,\,\vec{c}]$$
D
$$[\vec{d} \,\,\,\,\,\vec{c} \,\,\,\,\,\vec{a}]+[\vec{b} \,\,\,\,\,\vec{d} \,\,\,\,\,\vec{a}]+[\vec{c} \,\,\,\,\,\vec{d} \,\,\,\,\,\vec{b}]$$
4
JEE Main 2023 (Online) 11th April Morning Shift
+4
-1

For any vector $$\vec{a}=a_{1} \hat{i}+a_{2} \hat{j}+a_{3} \hat{k}$$, with $$10\left|a_{i}\right|<1, i=1,2,3$$, consider the following statements :

(A): $$\max \left\{\left|a_{1}\right|,\left|a_{2}\right|,\left|a_{3}\right|\right\} \leq|\vec{a}|$$

(B) : $$|\vec{a}| \leq 3 \max \left\{\left|a_{1}\right|,\left|a_{2}\right|,\left|a_{3}\right|\right\}$$

A
Only (B) is true
B
Only (A) is true
C
Neither (A) nor (B) is true
D
Both (A) and (B) are true
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