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APEX Calculus

Exercises 1.7 Review exercises

Exercise Group.

Evaluate the limit.

1.

\(\lim\limits_{x\to 5}{\frac{x^{2}+4x-45}{x^{2}-4x-5}}\)

2.

\(\lim\limits_{x\to 7}{\frac{x^{2}-10x+21}{x^{2}-15x+56}}\)

3.

\(\lim\limits_{x\to 9}{\frac{x^{2}+9x+20}{x^{2}+7x+12}}\)

Exercise Group.

Approximate the limit numerically.

4.

\(\lim\limits_{x\to 0.6}{\frac{x^{2}+8.8x-5.64}{x^{2}+6.3x-4.14}}\)

5.

\(\lim\limits_{x\to 1.7}{\frac{x^{2}+4.3x-10.2}{x^{2}-2.9x+2.04}}\)

6.

Evaluate the given limits of the piecewise defined function.
\(f(x) ={\begin{cases}\displaystyle{x^{2}-3}\amp \text{if}\ x \lt 1\cr \displaystyle{x}\amp \text{if}\ x \ge 1\end{cases}}\)

(a)

\(\lim\limits_{x\to 1^-} f(x)\)

(b)

\(\lim\limits_{x\to 1^+} f(x)\)

(c)

\(\lim\limits_{x\to 1} f(x)\)

(d)

\(f(1)\)

7.

Numerically approximate the following limits.

(a)

\(\lim\limits_{x\to 4.6^{+}}\left({\frac{x^{2}-2.6x-9.2}{x^{2}-9.6x+23}}\right)\)

(b)

\(\lim\limits_{x\to 4.6^{-}}\left({\frac{x^{2}-2.6x-9.2}{x^{2}-9.6x+23}}\right)\)

8.

Give an example of a function \(f\) for which \(\lim\limits_{x\to 0} f(x)\) does not exist.

9.

Use an \(\varepsilon\)-\(\delta\) proof to prove that \(\lim\limits_{x\to 1}(5x-2)=3\text{.}\)

10.

Let \(\lim\limits_{x\to0} f(x) = 1\) and \(\lim\limits_{x\to0} g(x) = -1\text{.}\) Evaluate the following limits.

(a)

\(\lim\limits_{x\to0}(f+g)(x)\)

(b)

\(\lim\limits_{x\to0}(fg)(x)\)

(c)

\(\lim\limits_{x\to0}(f/g)(x)\)

(d)

\(\lim\limits_{x\to0}f(x)^{g(x)}\)

11.

Let \(f(x) = \begin{cases}{-x^{2}-4x-3}\amp x\lt-3\\{x^{2}+7x+14}\amp x\geq-3\end{cases}\text{.}\)
Is \(f\) continuous everywhere?

12.

Find \(\lim\limits_{x\to e} \ln(x)\text{.}\)

13.

Approximate \(\displaystyle\lim_{x\to 2.5}{\frac{x^{2}+\left(-9.5\right)x+17.5}{x^{2}+\left(-1.5\right)x+\left(-2.5\right)}}\text{.}\)

14.

Use the Bisection Method to approximate, accurate to two decimal places, the root of \(g(x) = {x^{3}+4x^{2}+6x+\left(-3\right)}\) on \([0.3,0.4]\text{.}\)

15.

Give maximal intervals on which each of the following functions are continuous.

(a)

\(\dfrac{1}{e^x+1}\)

(b)

\({\frac{1}{x^{2}-1}}\)

(c)

\({\sqrt{11-x}}\)

(d)

\({\sqrt{11-x^{2}}}\)

16.

Use the graph of \(f(x)\) provided to answer the following.

(a)

\(\lim\limits_{x\to-3^-} f(x)\)

(b)

\(\lim\limits_{x\to-3^+} f(x)\)

(c)

\(\lim\limits_{x\to-3} f(x)\)

(d)

Where is \(f\) continuous?