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← JEE Main 2026 · 2 Apr · Shift 1
MathematicsSingle correct+4 / -1Question 19 of 75

JEE Main 2026 · 2 Apr · Shift 1, Mathematics question 19

Let [⋅][\cdot] denote the greatest integer function. Then the value of ∫03(ex+e−x[x]!)dx\displaystyle\int_0^3\left(\frac{e^x+e^{-x}}{[x]!}\right)dx is :

Choose one option
Answer and worked solution

Official answer: B

Split at the integers. [x]!=1,1,2[x]!=1,1,2 on [0,1)[0,1), [1,2)[1,2), [2,3)[2,3):
∫02(ex+e−x)dx+12∫23(ex+e−x)dx=(e2−e−2)+12(e3−e2+e−2−e−3).\int_0^2(e^x+e^{-x})dx+\frac12\int_2^3(e^x+e^{-x})dx=\left(e^2-e^{-2}\right)+\frac12\left(e^3-e^2+e^{-2}-e^{-3}\right).

Simplify. =12(e2+e3−1e2−1e3)=\dfrac12\left(e^2+e^3-\dfrac1{e^2}-\dfrac1{e^3}\right).

(B)