1
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If ${ }^9 P_5+5 \cdot{ }^9 P_4={ }^{10} P_r$, then the value of '$r$' is

A
4
B
8
C
5
D
7
2
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If ' $\theta$ ' is the angle between two vectors $\vec{a}$ and $\vec{b}$ such that $|\vec{a}|=7,|\vec{b}|=1$ and $|\vec{a} \times \vec{b}|^2=k^2-(\vec{a} \cdot \vec{b})^2$, then the values of $k$ and $\theta$ are

A
$k=1, \theta=45^{\circ}$
B
$k=7, \theta=60^{\circ}$
C
$k=49, \theta=90^{\circ}$
D
$k=7$ and $\theta$ is arbitrary
3
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Consider three points $P(\cos \alpha, \sin \beta), Q(\sin \alpha, \cos \beta)$ and $R(0,0)$, where $0<\alpha, \beta<\frac{\pi}{4}$. Then

A
$P$ lies on the line segment $R Q$.
B
$Q$ lies on the line segment $P R$.
C
$R$ lies on the line segment $P Q$.
D
$P, Q, R$ are non-collinear.
4
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

An $n \times n$ matrix is formed using 0, 1 and $-$1 as its elements. The number of such matrices which are skew symmetric is

A
$\frac{n(n-1)}{2}$
B
$(n-1)^2$
C
$2^{n(n-1) / 2}$
D
$3^{n(n-1) / 2}$
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12