微积分I(标准路径) · 免费预览

§5.4 Integration by parts (continued)

我们如何计算涉及基本函数乘积的不定积分,例如 $\int x \sin(x) \, dx$ 和 $\int x e^x \, dx$?

1. Using Integration by Parts Multiple Times

Using Integration by Parts Multiple Times

2. Evaluating Definite Integrals Using Integration by Parts

Evaluating Definite Integrals Using Integration by Parts

3. When

When

4. Summary

Summary

5. Two rounds on a power times exponential

Applying integration by parts twice to the integral ∫t2et dt\int t^2e^t\,dt yields which antiderivative?

6. Two rounds of parts

Evaluating ∫x2sin⁡(x) dx\int x^2\sin(x)\,dx requires by parts twice, and the final antiderivative is

7. The boomerang integral

For ∫ezsin⁡(z) dz\int e^z\sin(z)\,dz, applying parts twice and solving for the unknown integral gives

8. Choosing the toolkit

Which combination of techniques evaluates ∫x5cos⁡(x3) dx\int x^5\cos(x^3)\,dx?

9. Sibling of the classic product

Evaluating ∫s2e3s ds\int s^2e^{3s}\,ds by parts twice gives

10. Arctangent times a power

Using t21+t2=1−11+t2\frac{t^2}{1+t^2} = 1 - \frac{1}{1+t^2}, the integral ∫tarctan⁡(t) dt\int t\arctan(t)\,dt equals

11. When the pair is already there

The integral ∫e2xcos⁡(e2x) dx\int e^{2x}\cos(e^{2x})\,dx differs from ∫e2xcos⁡(ex) dx\int e^{2x}\cos(e^x)\,dx because

12. Classifying a pure substitution case

Among ∫x3sin⁡(x4) dx\int x^3\sin(x^4)\,dx and ∫x7sin⁡(x4) dx\int x^7\sin(x^4)\,dx, the correct classifications are

13. Accumulation from a decaying product

For F(x)=∫0xte−2t dtF(x) = \int_0^x te^{-2t}\,dt, by parts gives F(x)=−12xe−2x−14e−2x+14F(x) = -\frac{1}{2}xe^{-2x} - \frac{1}{4}e^{-2x} + \frac{1}{4}. Compute F(1)F(1), rounded to four decimals.

14. A clean by parts value

Using the antiderivative −tcos⁡(t)+sin⁡(t)-t\cos(t) + \sin(t) from the by parts computation, evaluate ∫0π/2tsin⁡(t) dt\int_0^{\pi/2}t\sin(t)\,dt.

15. Log times cube at one

Using the antiderivative 14t4ln⁡(t)−116t4\frac{1}{4}t^4\ln(t) - \frac{1}{16}t^4, evaluate ∫1et3ln⁡(t) dt\int_1^e t^3\ln(t)\,dt as a decimal, rounded to four places.

16. The boomerang move is legitimate

When integration by parts reproduces the original integral on the other side, collecting like integrals and solving algebraically is a valid way to finish.

进入交互式练习

免费注册 · 即时批改 · 自动安排间隔复习。

免费开始这门课