Exercises

Practice consolidates “differentiating upper-limit integrals” and related techniques.

练习题

练习 1

Let F(x)=∫0xt2 dtF(x) = \int_0^x t^2 \, dt. Find F′(x)F'(x).

参考答案

Answer: F′(x)=x2F'(x) = x^2.

练习 2

Let F(x)=∫1x1t2 dtF(x) = \int_1^x \dfrac{1}{t^2} \, dt. Find F′(x)F'(x).

参考答案

Answer: F′(x)=1x2F'(x) = \dfrac{1}{x^2}.

练习 3

Let F(x)=∫0x3cos⁡t dtF(x) = \int_0^{x^3} \cos t \, dt. Find F′(x)F'(x).

参考答案

Answer: F′(x)=3x2cos⁡(x3)F'(x) = 3x^2 \cos(x^3).

练习 4

Let f(x)=∫0xe−t2cos⁡t dtf(x) = \int_0^x e^{-t^2} \cos t\,dt. Find f′(0)f'(0) and f′′(0)f''(0), and decide whether x=0x=0 is an extremum of f(x)f(x).

参考答案

Answer: f′(0)=1f'(0)=1, f′′(0)=0f''(0)=0, so x=0x=0 is not an extremum.

练习 5

改编自 2022 考研数学一第 1 题

Given lim⁡x→1f(x)ln⁡x=1\lim\limits_{x\to1} \dfrac{f(x)}{\ln x}=1 with f(x)=∫0xet2sin⁡t dtf(x) = \int_0^x e^{t^2} \sin t\,dt, find f′(1)f'(1).

参考答案

Answer: f′(1)=esin⁡1f'(1) = e \sin 1.

练习 6

改编自 2023 考研数学一第 3 题

Let y=f(x)y=f(x) be given parametrically by {x=2t+∣t∣y=∣t∣sin⁡t\begin{cases}x=2t+|t|\\y=|t|\sin t\end{cases} and f(x)=∫0xet2sin⁡t dtf(x) = \int_0^x e^{t^2} \sin t\,dt. Find f′(0)f'(0).

参考答案

Answer: f′(0)=0f'(0) = 0.

练习 7

改编自 2024 考研数学一第 1 题

Given f(x)=∫0xecos⁡tdtf(x)=\int_0^x e^{\cos t} dt, find f′(x)f'(x) and f′′(x)f''(x).

参考答案

Answer: f′(x)=ecos⁡xf'(x)=e^{\cos x}, f′′(x)=−ecos⁡xsin⁡xf''(x)=-e^{\cos x}\sin x.

练习 8

改编自 2025 考研数学一第 1 题

Given f(x)=∫0xet2sin⁡t dtf(x) = \int_0^x e^{t^2} \sin t\,dt, find f′(x)f'(x) and f′′(x)f''(x).

参考答案

Answer: f′(x)=ex2sin⁡xf'(x) = e^{x^2} \sin x, f′′(x)=2xex2sin⁡x+ex2cos⁡xf''(x) = 2x e^{x^2} \sin x + e^{x^2} \cos x.

练习 9

改编自 2022 考研数学一第 17 题

Given y′=−12xy+2+xy'= -\dfrac{1}{2\sqrt{x}}y + 2 + \sqrt{x} with y(1)=3y(1)=3, and f(x)=∫0xet2sin⁡t dtf(x) = \int_0^x e^{t^2} \sin t\,dt, find f′(1)f'(1).

参考答案

Answer: f′(1)=esin⁡1f'(1) = e \sin 1.

练习 10

改编自 2023 考研数学一第 14 题

Let continuous f(x)f(x) satisfy f(x+2)−f(x)=xf(x+2)-f(x)=x, ∫02f(x)dx=0\int_0^2 f(x)dx=0, and F(x)=∫0xet2sin⁡t dtF(x) = \int_0^x e^{t^2} \sin t\,dt. Find F′(0)F'(0) and F′′(0)F''(0).

参考答案

Answer: F′(0)=0F'(0) = 0, F′′(0)=1F''(0) = 1.


总结

本文出现的符号

符号类型读音/说明在本文中的含义
F′(x),f′(x)F'(x), f'(x)数学符号导数变上限积分或相关函数的导数
F′′(x),f′′(x)F''(x), f''(x)数学符号二阶导数二阶导数,用于判断曲线性质

中英对照

中文术语英文术语音标说明
积分上限函数upper-limit integral function/ˈʌpər ˈlɪmɪt ɪnˈtɛɡrəl ˈfʌŋkʃən/形如 ∫axf(t) dt\int_a^x f(t)\,dt 的函数
变上限积分求导differentiation of variable-limit integrals/ˌdɪfəˌrɛnʃiˈeɪʃən əv ˈvɛəriəbəl ˈlɪmɪt ˈɪntɪɡrəlz/对上限含 xx 的定积分求导
参考答案reference answer/ˈrɛfərəns ˈænsər/折叠展示的解答说明