jee-main 2020 Q65

jee-main · India · session1_07jan_shift1 Indefinite & Definite Integrals Integral Equation with Symmetry or Substitution
If $f(a + b + 1 - x) = f(x)$, for all $x$, where $a$ and $b$ are fixed positive real numbers, then $\frac { 1 } { a + b } \int _ { a } ^ { b } x (f(x) + f(x + 1)) d x$ is equal to
(1) $\int _ { a - 1 } ^ { b - 1 } f(x + 1) d x$
(2) $\int _ { a - 1 } ^ { b - 1 } f(x) d x$
(3) $\int _ { a + 1 } ^ { b + 1 } f(x) d x$
(4) $\int _ { a + 1 } ^ { b + 1 } f(x + 1) d x$
If $f(a + b + 1 - x) = f(x)$, for all $x$, where $a$ and $b$ are fixed positive real numbers, then $\frac { 1 } { a + b } \int _ { a } ^ { b } x (f(x) + f(x + 1)) d x$ is equal to\\
(1) $\int _ { a - 1 } ^ { b - 1 } f(x + 1) d x$\\
(2) $\int _ { a - 1 } ^ { b - 1 } f(x) d x$\\
(3) $\int _ { a + 1 } ^ { b + 1 } f(x) d x$\\
(4) $\int _ { a + 1 } ^ { b + 1 } f(x + 1) d x$