Calculus Volume 1 · free preview

The Limit of a Function

The limit of f(x) as x approaches a is the value the outputs settle toward, which may exist even where the function is undefined, is read from tables and graphs, and comes in one-sided and infinite forms.

1. The idea of approach

The idea of approach

2. Estimating from tables and graphs

Estimating from tables and graphs

3. One-sided limits

One-sided limits

4. Limits that fail to exist

Limits that fail to exist

5. Limit at a hole

The function f(x) = (x^2 - 4)/(x - 2) is undefined at x = 2. What is the limit of f(x) as x approaches 2?

6. One-sided agreement

A function has left-hand limit 3 and right-hand limit 5 as x approaches 2. What is the two-sided limit at 2?

7. Table estimation

For f(x) = (sin x)/x near 0, a table gives f(0.1) about 0.9983, f(0.01) about 0.99998, and f(0.001) about 0.9999998, with matching values from the left. What limit do the values suggest?

8. Infinite limit versus limit at infinity

Which statement correctly distinguishes the two notations lim x to 2 of f equals infinity and lim x to infinity of f equals 2?

9. Oscillating nonexistence

Why does the limit of sin(1/x) as x approaches 0 fail to exist?

10. Limit of a constant function

The function f(x) = 7 takes the value 7 everywhere. What is the limit of f(x) as x approaches any real number a?

11. One-sided at an endpoint

The square root function is defined only for x at least 0. What is its right-hand limit as x approaches 0? Answer with a number.

12. Sign of an unbounded limit

As x approaches 0 from the right, 1/x grows without bound in the positive direction. What symbol describes this limit? Answer with the single word infinity.

13. Limit of 1 over x at infinity

The outputs of f(x) = 1/x settle toward a single number as x grows without bound. What is that number? Answer with a number.

14. Two-sided agreement value

A function has left-hand limit 7 and right-hand limit 7 at x = 3. What is its two-sided limit there? Answer with a number.

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