微积分I(标准路径) · 免费预览

§1.7 Limits, continuity, and differentiability (continued)

从图象上看,说当 $x \to a$ 时 $f$ 有极限 $L$ 是什么意思?这与 $f$ 在 $x = a$ 处有左极限和右极限有什么联系?

1. Summary

Summary

2. The derivative of a piecewise linear function

A function pp is built from five straight-line segments with slopes −2-2, −12-\frac{1}{2}, 11, 00, and 33 left to right, joined with corners, a jump at x=0x = 0, and a missing value at x=3x = 3. What does the graph of y=p′(x)y = p'(x) look like?

3. Cataloging failures on a piecewise linear graph

For the same pp: the two sides at x=0x = 0 approach 00 and −2-2, the value p(3)p(3) does not exist, and the graph has corner points at x=−2x = -2, 11, and 22. Where is pp discontinuous, and where not differentiable?

4. Reasoning backward from a derivative graph

A function hh has a derivative h′h' whose graph is piecewise constant with values ±1\pm 1, undefined at x=−2,0,2x = -2, 0, 2. What can be concluded about hh?

5. A cusp with a vertical tangent

Let g(x)=∣x∣g(x) = \sqrt{|x|}. What happens to the difference quotient ∣h∣h\frac{\sqrt{|h|}}{h} as hh approaches 00?

6. An impossible combination

Which function is differentiable at a=3a = 3 but has no limit at a=3a = 3?

7. A limit that ignores a misplaced value

Let h(x)=1h(x) = 1 for every x≠−2x \ne -2, with h(−2)=4h(-2) = 4. What is true at a=−2a = -2?

8. A cusp quotient at a sample point

For g(x)=∣x∣g(x) = \sqrt{|x|}, evaluate the difference quotient value ∣0.01∣0.01\frac{\sqrt{|0.01|}}{0.01}, rounded to three decimals.

9. The other side of the cusp

For the same g(x)=∣x∣g(x) = \sqrt{|x|}, evaluate ∣−0.001∣−0.001\frac{\sqrt{|-0.001|}}{-0.001}, rounded to two decimals.

10. Continuous everywhere yet not differentiable somewhere

A function can be continuous at every point and still fail to be differentiable at some point.

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