出几道求导函数的高考题,要求:原函数的结构有一定的复杂度但是不失优美,导函数结构不能复杂,不涉及到高...

Erstellt am: 8. Januar 2026

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Frage

出几道求导函数的高考题,要求:原函数的结构有一定的复杂度但是不失优美,导函数结构不能复杂,不涉及到高等数学的内容。

Antwort

下面给你 8 道“高考风格”的求导题:原函数结构稍复杂、形式优美(常见于构造与化简),但导函数都比较干净,不涉及高数内容(只用到积/商/链式、指数对数、三角基本求导)。


1)对数 + 幂:把“复杂”藏在对数里

求导:

y=ln(x2+1x21)y=\ln\left(\frac{x^2+1}{x^2-1}\right)

提示lnAB=lnAlnB\ln\frac{A}{B}=\ln A-\ln B


2)指数“配对”:让指数项自己抵消

求导:

y=exsinx+excosxy=e^x\sin x+e^x\cos x

特点:原函数看着两项,求导后会出现漂亮的合并。


3)三角复合:结构优雅,导数简单

求导:

y=sin(ln(1+x))y=\sin\left(\ln(1+x)\right)

提示:链式法则,外层 sin\sin,内层 ln(1+x)\ln(1+x)


4)对称式商:商法则一出就“消”

求导:

y=x+1x1+x1x+1y=\frac{x+1}{x-1}+\frac{x-1}{x+1}

特点:原式对称,化简后求导很快。


5)根式 + 有理化风:看似根式,导数很规整

求导:

y=x2+1x21y=\sqrt{x^2+1}-\sqrt{x^2-1}

提示:直接求导也行;想更“高考味”可以先配合有理化观察结构。


6)构造积:原函数像“展开麻烦”,但导数整洁

求导:

y=(x2+1)exy=(x^2+1)\,e^{x}

特点:积的结构标准,导数可一行整理成同因子形式。


7)“平方嵌套”复合:外层平方让导数很干净

求导:

y=(ln(x2+1))2y=\left(\ln(x^2+1)\right)^2

提示:外层 u2u^2,内层 u=ln(x2+1)u=\ln(x^2+1)


8)三角恒等式改造题:原式优美,导数极简

求导:

y=ln(secx+tanx)y=\ln\left(\sec x+\tan x\right)

(定义域按可取处讨论) 特点:这是很经典的“高考压轴风格”结构,求导后会非常简。


如果你希望我把这些题按“高考题面”包装成完整题(含定义域、化简步骤、标准答案、易错点),或者想要 同一难度再出 10 道(侧重对数/指数/三角/根式某一类),我可以继续给你成套版本。

Frage

给出答案

Antwort

下面给出前面 8 题的标准求导结果(含关键化简思路,尽量简洁)。


1)y=ln(x2+1x21)\displaystyle y=\ln\left(\frac{x^2+1}{x^2-1}\right)

y=ln(x2+1)ln(x21)y=\ln(x^2+1)-\ln(x^2-1) y=2xx2+12xx21=2x[(x21)(x2+1)](x2+1)(x21)=4xx41y'=\frac{2x}{x^2+1}-\frac{2x}{x^2-1} =\frac{2x\big[(x^2-1)-(x^2+1)\big]}{(x^2+1)(x^2-1)} =-\frac{4x}{x^4-1}

2)y=exsinx+excosx\displaystyle y=e^x\sin x+e^x\cos x

y=exsinx+excosx+excosxexsinx=2excosxy'=e^x\sin x+e^x\cos x+e^x\cos x-e^x\sin x=2e^x\cos x

3)y=sin(ln(1+x))\displaystyle y=\sin(\ln(1+x))

y=cos(ln(1+x))11+x=cos(ln(1+x))1+xy'=\cos(\ln(1+x))\cdot \frac{1}{1+x} =\frac{\cos(\ln(1+x))}{1+x}

4)y=x+1x1+x1x+1\displaystyle y=\frac{x+1}{x-1}+\frac{x-1}{x+1}

先化简:

x+1x1=1+2x1,x1x+1=12x+1\frac{x+1}{x-1}=1+\frac{2}{x-1},\quad \frac{x-1}{x+1}=1-\frac{2}{x+1} y=2+2x12x+1y=2+\frac{2}{x-1}-\frac{2}{x+1} y=2(x1)2+2(x+1)2y'=-\frac{2}{(x-1)^2}+\frac{2}{(x+1)^2}

也可合并成:

y=2[(x1)2(x+1)2](x21)2=8x(x21)2y'=\frac{2\big[(x-1)^2-(x+1)^2\big]}{(x^2-1)^2} =-\frac{8x}{(x^2-1)^2}

5)y=x2+1x21\displaystyle y=\sqrt{x^2+1}-\sqrt{x^2-1}

y=xx2+1xx21y'=\frac{x}{\sqrt{x^2+1}}-\frac{x}{\sqrt{x^2-1}}

6)y=(x2+1)ex\displaystyle y=(x^2+1)e^x

y=(2x)ex+(x2+1)ex=ex(x2+2x+1)=ex(x+1)2y'=(2x)e^x+(x^2+1)e^x=e^x(x^2+2x+1)=e^x(x+1)^2

7)y=(ln(x2+1))2\displaystyle y=\big(\ln(x^2+1)\big)^2

y=2ln(x2+1)2xx2+1=4xln(x2+1)x2+1y'=2\ln(x^2+1)\cdot \frac{2x}{x^2+1} =\frac{4x\ln(x^2+1)}{x^2+1}

8)y=ln(secx+tanx)\displaystyle y=\ln(\sec x+\tan x)

y=secxtanx+sec2xsecx+tanx=secx(tanx+secx)secx+tanx=secxy'=\frac{\sec x\tan x+\sec^2 x}{\sec x+\tan x} =\frac{\sec x(\tan x+\sec x)}{\sec x+\tan x} =\sec x

如果你想要我把每题的“易错点/得分点”也写出来(比如第 8 题如何一眼看出化简、定义域怎么写),我也可以直接补全。

Frage

同一难度再出 10 道同时给出答案。

Antwort

下面再给你 同一难度 10 道(原函数有结构感但不繁琐,导函数尽量简洁),并直接给出 答案


1

题: y=ln ⁣(x+x2+1)\displaystyle y=\ln\!\big(x+\sqrt{x^2+1}\big)
答:

y=1x2+1y'=\frac1{\sqrt{x^2+1}}

2

题: y=ln ⁣(1+sinx1sinx)\displaystyle y=\ln\!\left(\frac{1+\sin x}{1-\sin x}\right)
答:

y=2cosx=2secxy'=\frac{2}{\cos x}=2\sec x

3

题: y=arctan(2x)\displaystyle y=\arctan(2x)
答:

y=21+4x2y'=\frac{2}{1+4x^2}

4

题: y=ex(sinxcosx)\displaystyle y=e^{x}\,(\sin x-\cos x)
答:

y=2exsinxy'=2e^{x}\sin x

5

题: y=lnxx(x>0)\displaystyle y=\frac{\ln x}{x}\quad(x>0)
答:

y=1lnxx2y'=\frac{1-\ln x}{x^2}

6

题: y=ln(x2+x+1)\displaystyle y=\ln(x^2+x+1)
答:

y=2x+1x2+x+1y'=\frac{2x+1}{x^2+x+1}

7

题: y=1+x1x\displaystyle y=\sqrt{1+x}-\sqrt{1-x}
答:

y=121+x+121xy'=\frac{1}{2\sqrt{1+x}}+\frac{1}{2\sqrt{1-x}}

8

题: y=(x+1x)ex(x0)\displaystyle y=(x+\frac1x)e^{x}\quad(x\neq 0)
答:

y=ex ⁣(x+1x+11x2)y'=e^{x}\!\left(x+\frac1x+1-\frac1{x^2}\right)

9

题: y=ln(1+tanx)\displaystyle y=\ln(1+\tan x)(在可取处)
答:

y=sec2x1+tanx=secx(secxtanx)y'=\frac{\sec^2 x}{1+\tan x}=\sec x(\sec x-\tan x)

10

题: y=ln ⁣(x2+2x+2x2+2x+1)\displaystyle y=\ln\!\left(\frac{x^2+2x+2}{x^2+2x+1}\right)
答:

y=2(x+1)(x+1)2+12x+1y'=\frac{2(x+1)}{(x+1)^2+1}-\frac{2}{x+1}

如果你希望我把这 10 道也按“高考卷面格式”排版(题号、定义域提示、关键步骤、最终结果一栏),我也可以继续整理成一份成套题。

Frage

同一难度再出 10 道同时给出答案。

Gedanke

Creating derivative problems for high school calculus

I need to generate 10 derivative problems at a high school calculus level. The functions should be complex but with simple derivatives, and should involve polynomials, rationals, trig, exponentials, and logs. I'll aim for originality but ensure the derivatives are straightforward, possibly using cancellations or functions like ln(sin x). I'll craft these carefully!

Creating useful derivative problems

Okay, I think I’ve got a few good ideas for derivative problems. For example, we can use functions like y = ln(tan x), which has a simple sec^2/tan derivative, or y = ln(sin x) - ln(cos x) = ln(tan(x/2)), which has a clean derivative involving csc x. Another idea is y = (x^2-1)/x, which gives a simple, non-complex derivative. I’ll tweak and finalize the list!

Creating derivative problems with simple solutions

I think I’ve found some neat options like y = e^{-x}(sin x + cos x), which has a derivative of -2e^{-x} sin x—simple! Another idea is y = ln((1 + cos x)/sin x), with a derivative of -csc x. These should work since they follow the user’s requirement for manageable complexity and simple derivatives. I'll finalize this!

Verifying derivatives for clarity

I’m checking the derivatives of a few functions like y = ln(1 + cos x) - ln(sin x). The derivative worked out to -csc x, which looks good. For y = ln((1 - cos x)/sin x), I got csc x. Also, y = arctan((x - 1)/(x + 1)) simplifies nicely to 1/(x^2 + 1) after some algebra. Nice!

Finalizing function selection for derivatives

I'm trying a mix of functions to match the goal of moderate complexity with simple derivatives, like y = ln(x^2+1) + arctan(x). Some options, like y = ln((x+1)/(x-1)), have already appeared; others, like y = (x+1/x) ln x, might work but aren't super simple. After final review, I have 10 solid candidates.

Confirming derivatives for selected functions

I've confirmed the derivatives for several functions, like y = ln(1 + x^2) - 2 arctan(x), and others with simpler derivatives like y = x ln x - x. I’ve also verified that the derivatives of y = e^{-x}(sin x + cos x) and others hold up properly. Need to finish verifying algebra for some, but I'm getting closer to completing all ten.

Thought for 53s

Antwort

下面再给你 同一难度 10 道,并直接给出 导数答案(均在函数可导的取值范围内)。


1

题:   y=ex(sinx+cosx)\;y=e^{-x}(\sin x+\cos x)
答:   y=2exsinx\;y'=-2e^{-x}\sin x


2

题:   y=ln ⁣(1+cosxsinx)\;y=\ln\!\left(\dfrac{1+\cos x}{\sin x}\right)
答:   y=cscx\;y'=-\csc x


3

题:   y=ln ⁣(1cosxsinx)\;y=\ln\!\left(\dfrac{1-\cos x}{\sin x}\right)
答:   y=cscx\;y'=\csc x


4

题:   y=ln ⁣(x+x21)\;y=\ln\!\left(x+\sqrt{x^{2}-1}\right)
答:   y=1x21\;y'=\dfrac{1}{\sqrt{x^{2}-1}}


5

题:   y=arctan ⁣(x1x+1)\;y=\arctan\!\left(\dfrac{x-1}{x+1}\right)
答:   y=1x2+1\;y'=\dfrac{1}{x^{2}+1}


6

题:   y=(x1)ex\;y=(x-1)e^{x}
答:   y=xex\;y'=xe^{x}


7

题:   y=(x22x+2)ex\;y=(x^{2}-2x+2)e^{x}
答:   y=x2ex\;y'=x^{2}e^{x}


8

题:   y=ln ⁣(x2+1(x+1)2)\;y=\ln\!\left(\dfrac{x^{2}+1}{(x+1)^{2}}\right)
答:   y=2xx2+12x+1\;y'=\dfrac{2x}{x^{2}+1}-\dfrac{2}{x+1}


9

题:   y=xlnxx(x>0)\;y=x\ln x-x\quad(x>0)
答:   y=lnx\;y'=\ln x


10

题:   y=ln(secxtanx)\;y=\ln(\sec x-\tan x)
答:   y=secx\;y'=-\sec x


如果你还想要“更高考题面”的版本(附定义域、关键步骤、易错点、化简技巧),我也可以把这 20 题统一排成一套。

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