- 求下列复合函数的导数:
- `y = e^(-1/2 x^2 + 2x)`;
- `y = 2^(sin x^2)`;
- `y = tan^3 sqrt x`;
- `y = log_3^2 (x^3 + 2x + 1)`;
- `y = arcsin {:x/2:} + x^2/4 arccos {:x/2:}`;
- `y = arctan {:x^2/a:} + "arccot" {:a/x^2:}`;
- `y = ln cos x^2`;
- `y = ln tan {:x/2:} - cos x ln tan x`;
- `y = sin (cos^2 x) cos (sin^2 x)`;
- `y = sin [cos^2(tan^3 x)]`;
- `y = x sqrt(1+x^2)`;
- `y = root 3 ((1+x^3)/(1-x^3))`;
- `y = sqrt(x+sqrt(x+sqrt x))`;
- `y = root 3 (x + root 3 (x + root 3 x))`;
- `y = ln[ln(ln x)]`;
- `y = ln[ln^2(ln^3 x)]`;
- `y = 1/4 ln {:(x^2-1)/(x^2+1):}`;
- `y = 1/4 ln {:x^4/(1+x^4):} + 1/(4(1+x^4))`;
- `y = ln(sqrt(a^2+x^2) + sqrt(a^2-x^2))`;
- `y = x[sin(ln x) - cos(ln x)]`;
- `y = arcsin {:(x^2-1)/(x^2+1):}`;
- `y = arctan {:x/(1+sqrt(1-x^2)):}`;
- `y = ln(e^x + sqrt(1+e^(2xx)))`;
- `y = arctan(x + sqrt(1+x^2))`;
-
`y = x/2 sqrt(a^2+x^2) + a^2/2 ln(x + sqrt(a^2+x^2))`;
-
`y = x/2 sqrt(a^2-x^2) + a^2/2 arcsin {:x/a:}`;
-
`y = x arctan x - 1/2 ln (1+x^2) - 1/2 (arctan x)^2`;
-
`y = 1/(2 sqrt 2) arctan {:(sqrt 2 x)/sqrt(1+x^4):}
- 1/(4 sqrt 2) ln {:(sqrt(1+x^4) - sqrt 2 x)/(sqrt(1+x^4) +
sqrt 2 x):}`.
- 引入适当的中间变量, 求复合函数的导数:
- `y = ln(cos^2 x + sqrt(1+cos^4 x))`;
- `y = 1/2 arctan root 4 (1+x^4) - 1/4 ln {:(root 4
(1+x^4)-1)/(root 4 (1+x^4)+1):}`;
- `y = (arccos x)^2 [ln^2 (arccos x) - ln (arccos x) + 1/2]`;
- `y = (e^(-x^2) arcsin e^(-x^2)) / sqrt(1-e^(-2x^2)) + 1/2 ln
(1-e^(-2x^2))`;
- `y = (a^x(1-a^(2x))) / (1+a^(2x))^2 arctan a^-x`.
- 利用导数计算下列和式:
- `1 + 2x + 3x^2 + cdots + n x^(n-1)`;
- `1 + 2^2 x + 3^2 x^2 + cdots + n^2 x^(n-1)`;
- `sin x + 2 sin 2x + cdots + n sin nx`;
- `cos x + 4 cos 2x + cdots + n^2 cos nx`;
- `1/2 tan {:x/2:} + 1/4 tan {:x/4:} + cdots + 1/2^n tan
{:x/2^n:}`. (提示: `tan x = (ln cos x)'`).
- 证明由方程 `y^3 + 3y = x` 唯一地定义了 `(-oo, +oo)` 上的一个函数 `y =
y(x)`, 并求它的导函数 `y'(x)`.
- 求下列函数 `y = y(x)` 的反函数 `x = x(y)` 的存在域, 并求反函数 `x =
x(y)` 的导数:
- `y = x + ln x` (`x gt 0`);
- `y = x + e^x`;
- `y = sinh x`;
- `y = tanh x = (sinh x)/(cosh x)`.
- 证明下列函数 `y = y(x)` 除个别点外, 对值域中的每个 `y`
都有定义域中两个 `x` 与之对应. 求连续的两个反函数分支 `x = x_1(y)` 和
`x = x_2(y)` 的表达式, 并求它们的导数:
- `y = x^4 - 2x^2`;
- `y = (2x^2)/(1+x^2)`;
- `y = 2e^(-x^2) - e^(-2x^2)`.
- 求下列隐函数的导数:
- `y^2 - 2xy - x^2 + 2x = 0`;
- `x^2/a^2 + y^2/b^2 = 1`;
- `sqrt x + sqrt y = sqrt a`;
- `x^(2/3) + y^(2/3) = a^(2/3)`;
- `x^3 + y^3 - xy = 0`;
- `arctan {:y/x:} = ln sqrt(x^2+y^2)`.
- 求下列由参数方程表示的曲线的斜率 k:
- `{
x = a(t - sin t);
y = a(1 - cos t);
:}` (普通旋轮线);
- `{
x = (at^2)/(1+t^2);
y = (at^3)/(1+t^2);
:}` (蔓叶线);
- `{
x = a cos^3 theta;
y = a sin^3 theta;
:}` (四叶圆内旋轮线);
- `{
x = a tan t;
y = a cos^2 t;
:}` (箕舌线);
- `{
x = a theta cos theta;
y = a theta sin theta;
:}` (阿基米德螺线);
- `{
x = a(cos t + t sin t);
y = a(sin t - t cos t);
:}` (圆的渐开线).
- 用对数求导法求下列函数的导数:
- `y = x sqrt((1-x)/(1+x))`;
- `y = x^2/(2+x^2) root 3 ((1+x)^2/(2+x^2))`;
- `y = x^(ln x)`;
- `y = (1+x^2)^(arctan x)`;
- `y = (1+x)^(1/x)`;
- `y = x^(a^x) + x^(x^a) + x^(x^x)`;
- `y = (arccos x)^(x^2)`;
- `y = (sin x)^(cos x) (cos x)^(sin x)`.
- 设 a 为正常数. 证明:
- 旋轮线 `x^(2/3) + y^(2/3) = a^(2/3)`
的切线被坐标轴所截线段的长度为一常数;
- 曳物线 `x = a(ln tan t + cos 2t)`, `y = a sin 2t` `(0 lt t lt
pi/2)` 的切线上切点至它与 x 轴的交点的长度为一常数;
- 心脏线 `r = a(1-cos theta)` (r 为极径, `theta` 为极角)
的向径与切线间的夹角等于极角的一半;
- 双纽线 `r^2 = a^2 cos 2 theta`
的向径与切线间的夹角等于极角的两倍加一直角;
- 对数螺线 `r = ae^(m theta)` (m 为正常数)
的向径与切线间的夹角是一常量;
- 位于上半平面的光滑曲线 `y = f(x)` (即 `f(x) gt 0, AA x in RR`)
与其调制曲线 `y = f(x) sin ax` 在每个公共点处都相切,
即有相同的切线.
- 设 `a_1, a_2, cdots, a_n` 都是实数, 而
`f(x) = a_1 sin x + a_2 sin 2x + cdots + a_n sin nx`, `x in RR`.
假设已知对任意 `x in RR` 都有 `|f(x)| le |sin x|`, 证明: `|a_1 + 2a_2
+ cdots + na_n| le 1`.