1
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

Let 1 lies between the roots of the equation $y^2-m y+1=0$ and $[x]$ denotes the greatest integer function. Then the value of $\left[\left(\frac{4|x|}{x^2+16}\right)^m\right]$ is

A

5

B

4

C

0

D

1

2
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

Let $f(x)$ be a twice differentiable function in $[1,3]$ and $f(1)=f(3)$. Further if $\left|f^{\prime \prime}(x)\right| \leq 2$, then for all $x$ in $[1,3]$

A

$\left|\mathrm{f}^{\prime}(\mathrm{x})\right| \geq 4$

B

$\left|\mathrm{f}^{\prime}(\mathrm{x})\right| \leq-1$

C

$\left|\mathrm{f}^{\prime}(\mathrm{x})\right|>2$

D

$\left|\mathrm{f}^{\prime}(x)\right|<4$

3
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

The quantities $a_1, a_2, a_3, \ldots$ form an infinite decreasing G.P. If $a_1=1$, then the common ratio of the progression for which the expression $6 a_5-16 a_4-3 a_3+12 a_2$ is at a maximum is

A

$\frac{1}{4}$

B

$\frac{1}{2}$

C

$\frac{1}{3}$

D

$-\frac{1}{4}$

4
WB JEE 2026
MCQ (Single Correct Answer)
+2
-0.5
Change Language

If $f$ be a real valued function defined for all real numbers $x$ such that for some fixed $a>0$, it satisfies $f(x+a)=\frac{1}{2}+\sqrt{f(x)-(f(x))^2} \forall x$, then $f(x)$ is periodic with period

A

a

B

4a

C

$\frac{\mathrm{a}}{2}$

D

2 a