Skip to content
dronacharya.ai
← JEE Main 2022 · 29 Jun · Shift 1
MathematicsSingle correct+4 / -1Question 17 of 90

JEE Main 2022 · 29 Jun · Shift 1, Mathematics question 17

∫05cos⁡(π(x−[x2]))dx\displaystyle\int_0^5\cos\left(\pi\left(x-\left[\frac x2\right]\right)\right)dx,

where [t][t] denotes greatest integer less than or equal to tt, is equal to :

Choose one option
Answer and worked solution

Official answer: D

Pieces. On [0,2)[0,2) the integrand is cos⁡πx\cos\pi x, on [2,4)[2,4) it is cos⁡π(x−1)\cos\pi(x-1), on [4,5][4,5] it is cos⁡π(x−2)\cos\pi(x-2). Each whole period integrates to 0, and ∫45cos⁡πx dx=0\int_4^5\cos\pi x\,dx=0.

(D)