Calculus I · Limits and Continuity · Answer key

Practice Exam A Answer Key

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Compare one item at a time after completing Practice Exam A. For every mismatch, name the method you should have recognized before reading the next answer.

Complete published key

Practice Exam A answers

Use the numbering from the exam. If your answer differs, identify the method or condition you missed before moving to the next item.

  1. A1

    f(2)=7f(2)=7, while the limit is 44. The filled point gives the first; nearby graph behavior gives the second.

  2. A2

    Defined value, existing two-sided limit, equality between them.

  3. A3

    It records simultaneous numerator and denominator convergence to zero but does not determine their relative rates.

  4. A4

    IVT guarantees at least one attained intermediate value under continuity; it does not calculate or prove uniqueness.

  5. A5

    13-13.

  6. A6

    Factor and cancel to obtain x+3x+3; answer 66.

  7. A7

    Rationalization gives 1/(x+9+3)1/(\sqrt{x+9}+3); answer 1/61/6.

  8. A8

    Combine fractions to obtain 1/(2x)-1/(2x); at 22, answer 1/4-1/4.

  9. A9

    (7/2)(sin7x/7x)7/2(7/2)(\sin7x/7x)\to7/2.

  10. A10

    Squeezed between x2-x^2 and x2x^2; answer 00.

  11. A11

    Left 1-1, right 11; answer DNE\mathrm{DNE}.

  12. A12

    Numerator approaches 3>03>0; denominator changes sign. Left -\infty, right ++\infty.

  13. A13

    5/25/2.

  14. A14

    1-1.

  15. A15

    Hole at 11, vertical asymptote x=2x=2, horizontal asymptote y=1y=1.

  16. A16

    2k+1=32k+1=3, so k=1k=1.

  17. A17

    The polynomial is continuous; values at 1,21,2 are 1,7-1,7, so a root exists.

  18. A18

    δ=ε/2\delta=\varepsilon/2.

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Vocab
Limit
Math glossaryLimit
limxaf(x)=L\lim_{x\to a}f(x)=L

The value a function approaches as its input approaches a target.

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Function
Math glossaryFunction
y=f(x)y=f(x)

A rule or relation assigning exactly one output to each allowed input.

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Continuity
Math glossaryContinuity
limxaf(x)=f(a)\lim_{x\to a}f(x)=f(a)

At a point, the function value exists and equals the limit there.

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Domain
Math glossaryDomain
domf\operatorname{dom}f

The set of permitted input values.

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Math glossary