1
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

If $\int_0^1\left(\sum_{r=1}^{2013} \frac{x}{x^2+r^2}\right)\left(\prod_{r=1}^{2013}\left(x^2+r^2\right)\right) d x=\frac{1}{2}\left[\left(\prod_{r=1}^{2013}\left(1+r^2\right)-K^2\right]\right.$, then $K$ is

A

$\frac{2013(2014)(4027)}{6}$

B

$(2013)^{2013}$

C

$(2013)!$

D

$(2013!)^2$

2
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The least positive value of ' $a$ ' for which the equation $\int_0^x\left(t^2-8 t+13\right) d t=x \sin \frac{a}{x}$ has a solution is

A

$3 \pi$

B

$4 \pi$

C

$\pi$

D

$2 \pi$

3
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

Let all the points on the curve $x^2+y^2-10 x=0$ are reflected about the line $y=x+3$. If the locus of the reflected points is in the form $x^2+y^2+g x+f y+c=0$, then the value of $(g+f+c)$ is

A

38

B

-28

C

28

D

-38

4
WB JEE 2026
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The equation $|x+1|^{\log _{(x+1)}\left(3+2 x-x^2\right)}=(x-3)|x|$ has

A

no solution

B

two solutions

C

unique solution

D

infinite no. of solutions