Definite Integral Evaluation by Parts

Compute the exact numerical or symbolic value of a definite integral where integration by parts is the primary technique.

ap-calculus-ab None Q16 View
$x$25
$f ( x )$47
$f ^ { \prime } ( x )$23

The table above gives values of the differentiable function $f$ and its derivative $f ^ { \prime }$ at selected values of $x$. If $\int _ { 2 } ^ { 5 } f ( x ) \, d x = 14$, what is the value of $\int _ { 2 } ^ { 5 } x \cdot f ^ { \prime } ( x ) \, d x$?
(A) 13
(B) 27
(C) $\frac { 63 } { 2 }$
(D) 41
ap-calculus-bc 2012 Q4 (Free Response) View
The function $f$ is twice differentiable for $x > 0$ with $f ( 1 ) = 15$ and $f ^ { \prime \prime } ( 1 ) = 20$. Values of $f ^ { \prime }$, the derivative of $f$, are given for selected values of $x$ in the table above.
$x$11.11.21.31.4
$f ^ { \prime } ( x )$810121314.5

(a) Write an equation for the line tangent to the graph of $f$ at $x = 1$. Use this line to approximate $f ( 1.4 )$.
(b) Use a midpoint Riemann sum with two subintervals of equal length and values from the table to approximate $\int _ { 1 } ^ { 1.4 } f ^ { \prime } ( x ) d x$. Use the approximation for $\int _ { 1 } ^ { 1.4 } f ^ { \prime } ( x ) d x$ to estimate the value of $f ( 1.4 )$. Show the computations that lead to your answer.
(c) Use Euler's method, starting at $x = 1$ with two steps of equal size, to approximate $f ( 1.4 )$. Show the computations that lead to your answer.
(d) Write the second-degree Taylor polynomial for $f$ about $x = 1$. Use the Taylor polynomial to approximate $f ( 1.4 )$.
bac-s-maths 2024 Q3 7 marks View
A certification body is commissioned to evaluate two heating devices, one from brand A and the other from brand B.
Parts 1 and 2 are independent.
Part 1: device from brand A Using a probe, the temperature inside the combustion chamber of a brand A device was measured. Below is a representation of the temperature curve in degrees Celsius inside the combustion chamber as a function of time elapsed, expressed in minutes, since the combustion chamber was ignited.
By reading the graph:
  1. Give the time at which the maximum temperature is reached inside the combustion chamber.
  2. Give an approximate value, in minutes, of the duration during which the temperature inside the combustion chamber exceeds $300 ^ { \circ } \mathrm { C }$.
  3. We denote by $f$ the function represented on the graph. Estimate the value of $\frac { 1 } { 600 } \int _ { 0 } ^ { 600 } f ( t ) \mathrm { d } t$. Interpret the result.

Part 2: study of a function Let the function $g$ be defined on the interval $[0 ; + \infty [$ by: $$g ( t ) = 10 t \mathrm { e } ^ { - 0.01 t } + 20 .$$
  1. Determine the limit of $g$ at $+ \infty$.
  2. a. Show that for all $t \in \left[ 0 ; + \infty \left[ , \quad g ^ { \prime } ( t ) = ( - 0.1 t + 10 ) \mathrm { e } ^ { - 0.01 t } \right. \right.$. b. Study the variations of the function $g$ on $[0 ; + \infty [$ and construct its variation table.
  3. Prove that the equation $g ( t ) = 300$ has exactly two distinct solutions on $[0 ; + \infty [$. Give approximate values to the nearest integer.
  4. Using integration by parts, calculate $\int _ { 0 } ^ { 600 } g ( t ) \mathrm { d } t$.

Part 3: evaluation For a brand B device, the temperature in degrees Celsius inside the combustion chamber $t$ minutes after ignition is modelled on $[0 ; 600]$ by the function $g$.
The certification body awards one star for each criterion validated among the following four:
  • Criterion 1: the maximum temperature is greater than $320 ^ { \circ } \mathrm { C }$.
  • Criterion 2: the maximum temperature is reached in less than 2 hours.
  • Criterion 3: the average temperature during the first 10 hours after ignition exceeds $250 ^ { \circ } \mathrm { C }$.
  • Criterion 4: the temperature inside the combustion chamber must not exceed $300 ^ { \circ } \mathrm { C }$ for more than 5 hours.
Does each device obtain exactly three stars? Justify your answer.
cmi-entrance 2020 QA3 View
Calculate the following two definite integrals. It may be useful to first sketch the graph. $$\int_{1}^{e^{2}} \ln|x|\, dx \qquad \int_{-1}^{1} \frac{\ln|x|}{|x|}\, dx$$
csat-suneung 2016 Q20 4 marks View
Two polynomial functions $f ( x ) , g ( x )$ satisfy for all real numbers $x$ $$f ( - x ) = - f ( x ) , \quad g ( - x ) = g ( x )$$ For the function $h ( x ) = f ( x ) g ( x )$, $$\int _ { - 3 } ^ { 3 } ( x + 5 ) h ^ { \prime } ( x ) d x = 10$$ What is the value of $h ( 3 )$? [4 points]
(1) 1
(2) 2
(3) 3
(4) 4
(5) 5
csat-suneung 2019 Q25 3 marks View
Find the value of $\int _ { 0 } ^ { \pi } x \cos ( \pi - x ) d x$. [3 points]
csat-suneung 2022 Q30 (Calculus) 4 marks View
A function $f ( x )$ that is increasing and differentiable on the set of all real numbers satisfies the following conditions. (가) $f ( 1 ) = 1 , \int _ { 1 } ^ { 2 } f ( x ) d x = \frac { 5 } { 4 }$ (나) When the inverse function of $f ( x )$ is $g ( x )$, for all real numbers $x \geq 1$, $g ( 2 x ) = 2 f ( x )$. When $\int _ { 1 } ^ { 8 } x f ^ { \prime } ( x ) d x = \frac { q } { p }$, find the value of $p + q$. (Given that $p$ and $q$ are coprime natural numbers.) [4 points]
grandes-ecoles 2023 Q2 View
Find two real numbers $\alpha$ and $\beta$ such that: $$\forall n \in \mathbf{N}^*, \int_0^{\pi} (\alpha t^2 + \beta t) \cos(nt) \mathrm{d}t = \frac{1}{n^2}$$ then verify that if $t \in ]0, \pi]$, then: $$\forall n \in \mathbf{N}^*, \sum_{k=1}^n \cos(kt) = \frac{\sin\left(\frac{(2n+1)t}{2}\right)}{2\sin\left(\frac{t}{2}\right)} - \frac{1}{2}$$
jee-advanced 2014 Q55 View
The value of $$\int_{0}^{1} 4x^3 \left\{\frac{d^2}{dx^2}\left(1 - x^2\right)^5\right\} dx$$ is
jee-main 2025 Q4 View
Let $\int x ^ { 3 } \sin x \mathrm {~d} x = g ( x ) + C$, where $C$ is the constant of integration. If $8 \left( g \left( \frac { \pi } { 2 } \right) + g ^ { \prime } \left( \frac { \pi } { 2 } \right) \right) = \alpha \pi ^ { 3 } + \beta \pi ^ { 2 } + \gamma , \alpha , \beta , \gamma \in Z$, then $\alpha + \beta - \gamma$ equals :
(1) 48
(2) 55
(3) 62
(4) 47
jee-main 2025 Q11 View
Let $\mathrm { f } : \mathbf { R } \rightarrow \mathbf { R }$ be a twice differentiable function such that $f ( 2 ) = 1$. If $\mathrm { F } ( x ) = x f ( x )$ for all $x \in \mathbf { R }$, $\int _ { 0 } ^ { 2 } x \mathrm {~F} ^ { \prime } ( x ) \mathrm { d } x = 6$ and $\int _ { 0 } ^ { 2 } x ^ { 2 } \mathrm {~F} ^ { \prime \prime } ( x ) \mathrm { d } x = 40$, then $\mathrm { F } ^ { \prime } ( 2 ) + \int _ { 0 } ^ { 2 } \mathrm {~F} ( x ) \mathrm { d } x$ is equal to :
(1) 11
(2) 13
(3) 15
(4) 9
kyotsu-test 2012 QCourse2-IV-Q2 View
For a positive integer $n$ and a real number $a$, consider the function
$$f_n(a) = \int_0^{\pi} (\cos x + a\sin 2nx)^2\, dx$$
(1) When we transform $f_n(a)$ into
$$f_n(a) = \int_0^{\pi} \left\{\frac{1 + \cos \mathbf{L}\, x}{2} + a^2 \frac{1 - \cos \mathbf{M}\, nx}{2} + a(\sin(2n+1)x + \sin(2n-1)x)\right\} dx$$
and calculate the definite integral on the right side, we obtain
$$f_n(a) = \frac{\pi}{\mathbf{N}}\, a^2 + \frac{\mathbf{O}\, n}{\mathbf{P}\, n^2 - \mathbf{Q}}\, a + \frac{\pi}{\mathbf{R}}.$$
(2) Let $a_n$ denote the value of $a$ at which $f_n(a)$ is minimalized, and set $S_N = \sum_{n=1}^{N} \frac{a_n}{n}$.
Then
$$\begin{aligned} S_N &= -\frac{\mathbf{S}}{\pi} \sum_{n=1}^{N} \left(\frac{1}{2n - \mathbf{T}} - \frac{1}{2n + \mathbf{U}}\right) \\ &= -\frac{\mathbf{S}}{\pi} \left(\mathbf{V} - \frac{1}{\mathbf{W}N + \mathbf{U}}\right) \end{aligned}$$
Hence we obtain
$$\sum_{n=1}^{\infty} \frac{a_n}{n} = \lim_{N \to \infty} S_N = -\frac{\mathbf{Y}}{\pi}.$$
turkey-yks 2010 Q49 View
For the function $f$ whose graph is given above, $$\int_{1}^{3} \frac{x \cdot f'(x) - f(x)}{x^{2}}\, dx$$ What is the value of the integral?
A) $\frac{7}{2}$
B) $\frac{3}{2}$
C) $\frac{2}{3}$
D) $\frac{1}{3}$
E) $\frac{5}{4}$
turkey-yks 2014 Q46 View
f is a differentiable function on the set of real numbers and
$$\begin{aligned} & \int _ { 0 } ^ { 3 } f ( x ) d x = 2 \\ & \int _ { 0 } ^ { 3 } x f ^ { \prime } ( x ) d x = 1 \end{aligned}$$
Given this, what is the value of $\mathbf { f } \boldsymbol { ( } \mathbf { 3 } \boldsymbol { ) }$?
A) 0
B) 1
C) 2
D) 3
E) 4
turkey-yks 2015 Q45 View
For a function f defined on the set of real numbers and twice differentiable,
$$\begin{aligned} & f ( 1 ) = f ( 2 ) = 2 \\ & f ^ { \prime } ( 1 ) = f ^ { \prime } ( 2 ) = - 1 \end{aligned}$$
the following equalities are given.
Accordingly, what is the value of the integral $\int _ { 1 } ^ { 2 } x \cdot f ^ { \prime \prime } ( x ) d x$?
A) $- 1$
B) $- 2$
C) $- 3$
D) $\frac { - 1 } { 2 }$
E) $\frac { - 2 } { 3 }$
turkey-yks 2017 Q46 View
$\int _ { 1/2 } ^ { e } x \ln ( 2 x ) \, d x$\ What is the value of the integral?\ A) $\frac { e ^ { 2 } } { 2 }$\ B) $\frac { e ^ { 2 } - 1 } { 4 }$\ C) $\frac { e ^ { 2 } + 1 } { 16 }$\ D) 1\ E) 2