Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
Let $\mathrm{f}$ be derivable in $[0,1]$, then
MathematicsDefinite IntegrationWBJEEWBJEE 2022
Options:
  • A there exists $c \in(0,1)$ such that $\int_0^c f(x) d x=(1-c) f(c)$
  • B there does not exist any point $d \in(0,1)$ for which $\int_0^d f(x) d x=(1-d) f(d)$
  • C $\int_0^c f(x) d x$ does not exist, for any $c \in(0,1)$
  • D $\int_0^c f(x) d x$ is independent of $c, c \in(0,1)$
Solution:
1925 Upvotes Verified Answer
The correct answer is: there exists $c \in(0,1)$ such that $\int_0^c f(x) d x=(1-c) f(c)$
Let $g(x)=x \int_0^x f(t) d t-\int_0^x f(t) d t$
Now, $g(0)=0$
$g(1)=0$
By Rolle's Theorem
$g^{\prime}(x)=0$
for some $x \in(0,1)$
$g^{\prime}(x)=x f(x)+\int_0^x f(t) d t-f(x)=0$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.