Integral Inequalities and Limit of Integral Sequences

Prove inequalities involving integrals, bound integral expressions, or determine the limit of a sequence defined by integrals (e.g., Iā‚™ as nā†’āˆž).

jee-advanced 2021 Q3 View
Let $f : \left[ - \frac { \pi } { 2 } , \frac { \pi } { 2 } \right] \rightarrow \mathbb { R }$ be a continuous function such that $$f ( 0 ) = 1 \text { and } \int _ { 0 } ^ { \frac { \pi } { 3 } } f ( t ) d t = 0$$ Then which of the following statements is (are) TRUE ?
(A) The equation $f ( x ) - 3 \cos 3 x = 0$ has at least one solution in $\left( 0 , \frac { \pi } { 3 } \right)$
(B) The equation $f ( x ) - 3 \sin 3 x = - \frac { 6 } { \pi }$ has at least one solution in $\left( 0 , \frac { \pi } { 3 } \right)$
(C) $\lim _ { x \rightarrow 0 } \frac { x \int _ { 0 } ^ { x } f ( t ) d t } { 1 - e ^ { x ^ { 2 } } } = - 1$
(D) $\lim _ { x \rightarrow 0 } \frac { \sin x \int _ { 0 } ^ { x } f ( t ) d t } { x ^ { 2 } } = - 1$
jee-main 2022 Q76 View
If $b_n = \int_0^{\frac{\pi}{2}} \frac{\cos^2 nx}{\sin x} dx$, $n \in \mathbb{N}$, then
(1) $b_3 - b_2, b_4 - b_3, b_5 - b_4$ are in an A.P. with common difference $-2$
(2) $\frac{1}{b_3 - b_2}, \frac{1}{b_4 - b_3}, \frac{1}{b_5 - b_4}$ are in an A.P. with common difference $2$
(3) $b_3 - b_2, b_4 - b_3, b_5 - b_4$ are in a G.P.
(4) $\frac{1}{b_3 - b_2}, \frac{1}{b_4 - b_3}, \frac{1}{b_5 - b_4}$ are in an A.P. with common difference $-2$
jee-main 2022 Q74 View
$I = \int _ { \frac { \pi } { 4 } } ^ { \frac { \pi } { 3 } } \left( \frac { 8 \sin x - \sin 2 x } { x } \right) d x$. Then
(1) $\frac { \pi } { 2 } < I < \frac { 3 \pi } { 4 }$
(2) $\frac { \pi } { 5 } < I < \frac { 5 \pi } { 12 }$
(3) $\frac { 5 \pi } { 12 } < I < \frac { \sqrt { 2 } } { 3 } \pi$
(4) $\frac { 3 \pi } { 4 } < I < \pi$
jee-main 2024 Q74 View
The value of $k \in \mathrm {~N}$ for which the integral $I _ { n } = \int _ { 0 } ^ { 1 } \left( 1 - x ^ { k } \right) ^ { n } d x , n \in \mathbb { N }$, satisfies $147 I _ { 20 } = 148 I _ { 21 }$ is
(1) 14
(2) 8
(3) 10
(4) 7
mat 2009 Q3 View
3. For APPLICANTS IN $\left\{ \begin{array} { l } \text { MATHEMATICS } \\ \text { MATHEMATICS \& STATISTICS } \\ \text { MATHEMATICS \& PHILOSOPHY } \\ \text { MATHEMATICS \& COMPUTER SCIENCE } \end{array} \right\}$ ONLY.
Computer Science applicants should turn to page 14. For a positive whole number $n$, the function $f _ { n } ( x )$ is defined by
$$f _ { n } ( x ) = \left( x ^ { 2 n - 1 } - 1 \right) ^ { 2 } .$$
(i) On the axes provided opposite, sketch the graph of $y = f _ { 2 } ( x )$ labelling where the graph meets the axes.
(ii) On the same axes sketch the graph of $y = f _ { n } ( x )$ where $n$ is a large positive integer.
(iii) Determine
$$\int _ { 0 } ^ { 1 } f _ { n } ( x ) \mathrm { d } x$$
(iv) The positive constants $A$ and $B$ are such that
$$\int _ { 0 } ^ { 1 } f _ { n } ( x ) \mathrm { d } x \leqslant 1 - \frac { A } { n + B } \text { for all } n \geqslant 1 .$$
Show that
$$( 3 n - 1 ) ( n + B ) \geqslant A ( 4 n - 1 ) n ,$$
and explain why $A \leqslant 3 / 4$.
(v) When $A = 3 / 4$, what is the smallest possible value of $B$ ? [Figure]
tmua 2016 Q18 1 marks View
Consider this statement about a function $f ( x )$ :
$\left( ^ { * } \right)$ If $( f ( x ) ) ^ { 2 } \leq 1$ for all $- 1 \leq x \leq 1$ then $\int _ { - 1 } ^ { 1 } ( f ( x ) ) ^ { 2 } \mathrm {~d} x \leq \int _ { - 1 } ^ { 1 } f ( x ) \mathrm { d } x$
Which one of the following functions provides a counterexample to (*)?
tmua 2020 Q13 1 marks View
$\mathrm { f } ( x )$ is a function for which
$$\int _ { 0 } ^ { 3 } ( \mathrm { f } ( x ) ) ^ { 2 } \mathrm {~d} x + \int _ { 0 } ^ { 3 } \mathrm { f } ( x ) \mathrm { d } x = \int _ { 0 } ^ { 1 } \mathrm { f } ( x ) \mathrm { d } x$$
Which of the following claims about $\mathrm { f } ( x )$ is/are necessarily true? I $\mathrm { f } ( x ) \leq 0$ for some $x$ with $1 \leq x \leq 3$ II $\int _ { 0 } ^ { 3 } \mathrm { f } ( x ) \mathrm { d } x \leq \int _ { 0 } ^ { 1 } \mathrm { f } ( x ) \mathrm { d } x$
A neither of them
B I only
C II only
D I and II
tmua 2021 Q12 1 marks View
Which of the following statements about polynomials $f$ and $g$ is/are true?
I If $\mathrm { f } ( x ) \geq \mathrm { g } ( x )$ for all $x \geq 0$, then $\int _ { 0 } ^ { x } \mathrm { f } ( t ) \mathrm { d } t \geq \int _ { 0 } ^ { x } \mathrm {~g} ( t ) \mathrm { d } t$ for all $x \geq 0$.
II If $\mathrm { f } ( x ) \geq \mathrm { g } ( x )$ for all $x \geq 0$, then $\mathrm { f } ^ { \prime } ( x ) \geq \mathrm { g } ^ { \prime } ( x )$ for all $x \geq 0$.
III If $\mathrm { f } ^ { \prime } ( x ) \geq \mathrm { g } ^ { \prime } ( x )$ for all $x \geq 0$, then $\mathrm { f } ( x ) \geq \mathrm { g } ( x )$ for all $x \geq 0$.
A none of them
B I only
C II only
D III only
E I and II only F I and III only G II and III only H I, II and III
tmua 2022 Q12 1 marks View
Place the following integrals in order of size, starting with the smallest.
$$\begin{aligned} & P = \int _ { 0 } ^ { 1 } 2 ^ { \sqrt { x } } \mathrm {~d} x \\ & Q = \int _ { 0 } ^ { 1 } 2 ^ { x } \mathrm {~d} x \\ & R = \int _ { 0 } ^ { 1 } ( \sqrt { 2 } ) ^ { x } \mathrm {~d} x \end{aligned}$$
A $P < Q < R$
B $P < R < Q$
C $Q < P < R$
D $Q < R < P$
E $\quad R < P < Q$ F $R < Q < P$
tmua 2023 Q20 1 marks View
Let $f$ be a polynomial with real coefficients. The integral $I _ { p , q }$ where $p < q$ is defined by
$$I _ { p , q } = \int _ { p } ^ { q } ( f ( x ) ) ^ { 2 } - ( f ( | x | ) ) ^ { 2 } \mathrm {~d} x$$
Which of the following statements must be true? $1 I _ { p , q } = 0$ only if $0 < p$ $2 f ^ { \prime } ( x ) < 0$ for all $x$ only if $I _ { p , q } < 0$ for all $p < q < 0$ $3 \quad I _ { p , q } > 0$ only if $p < 0$
A none of them B 1 only C 2 only D 3 only E 1 and 2 only F 1 and 3 only G 2 and 3 only H 1, 2 and 3
turkey-yks 2013 Q49 View
Let $n$ be a natural number,
$$\begin{aligned} & f _ { n } : [ n , n + 1 ) \rightarrow \left[ 0 , \frac { 1 } { 2 ^ { n } } \right) \\ & f _ { n } ( x ) = \frac { ( x - n ) ^ { 2 } } { 2 ^ { n } } \end{aligned}$$
The regions between the functions defined in this form and the x-axis are given shaded in the figure below.
Accordingly, what is the sum of the areas of all shaded regions in square units?
A) $\frac { 2 } { 3 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 5 } { 6 }$
D) $\frac { 8 } { 9 }$
E) $\frac { 11 } { 12 }$
turkey-yks 2018 Q23 View
For an increasing and continuous function f defined on the set of real numbers,
$$\begin{aligned} & f ( 0 ) = 2 \\ & f ( 1 ) = 3 \\ & f ( 2 ) = 4 \end{aligned}$$
equalities are given.
Accordingly, the value of the integral $\int _ { 0 } ^ { 2 } f ( x ) d x$ could be which of the following?
A) 4 B) 4.5 C) 6 D) 7.5 E) 8
turkey-yks 2025 Q26 View
Let $m$ be a positive real number. In the rectangular coordinate plane, the region between the graph of a function $f$ defined on the closed interval $[-m, m]$ and the $x$-axis is divided into four regions and these regions are colored as shown in the figure. The areas of these regions, which are different from each other, are denoted by $A, B, C$ and $D$ as shown in the figure.
$$\int_{-m}^{m} |f(x)|\, dx = \int_{-m}^{m} f(x)\, dx + \int_{0}^{m} 2 \cdot f(x)\, dx$$
Given that, which of the following is the integral $\int_{-m}^{m} f(x)\, dx$ equal to?
A) $A + B$ B) $A + C$ C) $A + D$ D) $B + C$ E) $C + D$