1
WB JEE 2024
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Let $$\mathrm{N}$$ be the number of quadratic equations with coefficients from $$\{0,1,2, \ldots, 9\}$$ such that 0 is a solution of each equation. Then the value of $$\mathrm{N}$$ is

A
29
B
39
C
90
D
81
2
WB JEE 2024
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If $$a, b, c$$ are distinct odd natural numbers, then the number of rational roots of the equation $$a x^2+b x+c=0$$

A
must be 0
B
must be 1
C
must be 2
D
cannot be determined from the given data
3
WB JEE 2024
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The numbers $$1,2,3, \ldots \ldots, \mathrm{m}$$ are arranged in random order. The number of ways this can be done, so that the numbers $$1,2, \ldots \ldots ., \mathrm{r}(\mathrm{r}<\mathrm{m})$$ appears as neighbours is

A
$$(m-r)$$ !
B
$$(\mathrm{m}-\mathrm{r}+1)$$ !
C
$$(\mathrm{m}-\mathrm{r})!\mathrm{r}$$ !
D
$$(\mathrm{m}-\mathrm{r}+1)!\mathrm{r}$$ !
4
WB JEE 2024
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If $$A=\left(\begin{array}{cc}\cos \theta & -\sin \theta \\ \sin \theta & \cos \theta\end{array}\right)$$ and $$\theta=\frac{2 \pi}{7}$$, then $$A^{100}=A \times A \times \ldots .(100$$ times) is equal to

A
$$ \left(\begin{array}{cc} \cos 2 \theta & -\sin 2 \theta \\ \sin 2 \theta & \cos 2 \theta \end{array}\right) $$
B
$$ \left(\begin{array}{cc} \cos \theta & -\sin \theta \\ \sin \theta & \cos \theta \end{array}\right) $$
C
$$ \left(\begin{array}{ll} 1 & 0 \\ 0 & 1 \end{array}\right) $$
D
$$ \left(\begin{array}{cc} 0 & -1 \\ 1 & 0 \end{array}\right) $$
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