1
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

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

2
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

$-\frac{1}{4}$

3
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

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

Four natural numbers selected at random are multiplied together, then the probability that the digit in the unit's place in the product be $1,3,7$ or 9 is

A

$\frac{16}{625}$

B

$\frac{18}{625}$

C

$\frac{4}{625}$

D

$\frac{5}{625}$