Chapter 1

Algebra and Trigonometry Real Mathematics, Real People · 541 exercises

Problem 66

\((a)\) find \((f \circ g)(x)\) and \((g \circ f)(x),\) \((b)\) determine algebraically whether \((f \circ g)(x)=(g \circ f)(x),\) and \((c)\) use a graphing utility to complete a table of values for the two compositions to confirm your answer to part \((b).\) $$f(x)=\frac{6}{3 x-5}, \quad g(x)=-x$$

3 step solution

Problem 66

Determine algebraically whether the function is one-to-one. Verify your answer graphically. If the function is one-to-one, find its inverse. $$q(x)=(x-5)^{2}, \quad x \leq 5$$

3 step solution

Problem 66

Determine whether the statement is true or false. Justify your answer. The graph of a linear equation can have either no \(x\) -intercepts or only one \(x\) -intercept.

3 step solution

Problem 66

Find the domain of the function. $$f(x)=\frac{\sqrt{x+6}}{6+x}$$

3 step solution

Problem 66

Determine whether the lines \(L_{1}\) and \(L_{2}\) passing through the pairs of points are parallel, perpendicular, or neither. $$\begin{array}{l} L_{1}:(4,8),(-4,2) \\ L_{2}:(3,-5),\left(-1, \frac{1}{3}\right) \end{array}$$

3 step solution

Problem 67

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$h(x)=x^{2}+6$$

3 step solution

Problem 67

Determine algebraically whether the function is one-to-one. Verify your answer graphically. If the function is one-to-one, find its inverse. $$f(x)=\sqrt{2 x+3}$$

3 step solution

Problem 67

Determine whether the statement is true or false. Justify your answer. Writing Your employer offers you a choice of wage scales: a monthly salary of \(\$ 3000\) plus commission of \(7 \%\) of sales or a salary of \(\$ 3400\) plus a \(5 \%\) commission. Write a short paragraph discussing how you would choose your option. At what sales level would the options yield the same salary?

4 step solution

Problem 67

Use a graphing utility to graph the function. Find the domain and range of the function. $$f(x)=\sqrt{16-x^{2}}$$

3 step solution

Problem 68

Determine whether the statement is true or false. Justify your answer.The graphs of \(f(x)=|x|+6\) and \(f(x)=|-x|+6\) are identical.

3 step solution

Problem 68

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$f(x)=-x^{2}-8$$

4 step solution

Problem 68

Determine algebraically whether the function is one-to-one. Verify your answer graphically. If the function is one-to-one, find its inverse. $$f(x)=\sqrt{x-2}$$

3 step solution

Problem 68

Use a graphing utility to graph the function. Find the domain and range of the function. $$f(x)=\sqrt{x^{2}+1}$$

4 step solution

Problem 69

Use the fact that the graph of \(y=f(x)\) has \(x\) -intercepts at \(x=2\) and \(x=-3\) to find the \(x\) -intercepts of the given graph. If not possible, state the reason.$$y=f(-x)$$.

2 step solution

Problem 69

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$f(x)=\sqrt{1-x}$$

3 step solution

Problem 69

Determine algebraically whether the function is one-to-one. Verify your answer graphically. If the function is one-to-one, find its inverse. $$f(x)=|x-2|, \quad x \leq 2$$

2 step solution

Problem 69

Perform the operation and write the result in standard form. \((9 x-4)+\left(2 x^{2}-x+15\right)\)

3 step solution

Problem 69

Use a graphing utility to graph the function. Find the domain and range of the function. $$g(x)=|2 x+3|$$

3 step solution

Problem 69

Write the slope-intercept forms of the equations of the lines through the given point (a) parallel to the given line and (b) perpendicular to the given line. $$\left(-\frac{2}{3}, \frac{7}{8}\right), \quad 3 x+4 y=7$$

3 step solution

Problem 70

Use the fact that the graph of \(y=f(x)\) has \(x\) -intercepts at \(x=2\) and \(x=-3\) to find the \(x\) -intercepts of the given graph. If not possible, state the reason.$$y=2 f(x)$$.

3 step solution

Problem 70

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$g(t)=\sqrt[3]{t-1}$$

4 step solution

Problem 70

Determine algebraically whether the function is one-to-one. Verify your answer graphically. If the function is one-to-one, find its inverse. $$f(x)=\frac{x^{2}}{x^{2}+1}, \quad x \geq 0$$

3 step solution

Problem 70

Perform the operation and write the result in standard form. \(\left(3 x^{2}-5\right)\left(-x^{2}+1\right)\)

3 step solution

Problem 70

Use a graphing utility to graph the function. Find the domain and range of the function. $$g(x)=|3 x-5|$$

3 step solution

Problem 70

Write the slope-intercept forms of the equations of the lines through the given point (a) parallel to the given line and (b) perpendicular to the given line. $$\left(\frac{2}{5},-1\right), \quad 3 x-2 y=6$$

3 step solution

Problem 71

Use the fact that the graph of \(y=f(x)\) has \(x\) -intercepts at \(x=2\) and \(x=-3\) to find the \(x\) -intercepts of the given graph. If not possible, state the reason.$$y=f(x)+2$$.

4 step solution

Problem 71

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$f(x)=|x+2|$$

3 step solution

Problem 71

Find two functions \(f\) and \(g\) such that \((f \circ g)(x)=h(x)\) (There are many correct answers.) $$h(x)=(2 x+1)^{2}$$

3 step solution

Problem 71

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=4 x-9$$

3 step solution

Problem 71

Write the area \(A\) of a circle as a function of its circumference \(C .\)

3 step solution

Problem 72

Use the fact that the graph of \(y=f(x)\) has \(x\) -intercepts at \(x=2\) and \(x=-3\) to find the \(x\) -intercepts of the given graph. If not possible, state the reason.$$y=f(x-3)$$.

3 step solution

Problem 72

Use a graphing utility to graph the function and determine whether it is even, odd, or neither. $$f(x)=-|x-5|$$

3 step solution

Problem 72

Find two functions \(f\) and \(g\) such that \((f \circ g)(x)=h(x)\) (There are many correct answers.) $$h(x)=(1-x)^{3}$$

4 step solution

Problem 72

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=3 x$$

3 step solution

Problem 72

Write the area \(A\) of an equilateral triangle as a function of the length \(s\) of its sides.

3 step solution

Problem 72

Write the slope-intercept forms of the equations of the lines through the given point (a) parallel to the given line and (b) perpendicular to the given line. $$(-1.2,2.4), \quad 5 x+4 y=1$$

4 step solution

Problem 73

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=x^{5}$$

2 step solution

Problem 73

An open box of maximum volume is to be made from a square piece of material, 24 centimeters on a side, by cutting equal squares from the corners and turning up the sides. (See figure.) (a) The table shows the volume \(V\) (in cubic centimeters) of the box for various heights \(x\) (in centimeters). Use the table to estimate the maximum volume. $$\begin{array}{|c|c|} \hline \text { Teather } & \text { Volumes } \\ \hline 1 & 484 \\ 2 & 800 \\ 3 & 972 \\ 4 & 1024 \\ 5 & 980 \\ 6 & 864 \\ \hline \end{array}$$ (b) Plot the points \((x, V)\) from the table in part (a). Does the relation defined by the ordered pairs represent \(V\) as a function of \(x ?\) (c) If \(V\) is a function of \(x,\) write the function and determine its domain. (d) Use a graphing utility to plot the points from the table in part (a) with the function from part (c). How closely does the function represent the data? Explain.

4 step solution

Problem 74

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=x^{3}+1$$

3 step solution

Problem 74

Find two functions \(f\) and \(g\) such that \((f \circ g)(x)=h(x)\) (There are many correct answers.) $$h(x)=\sqrt{9-x}$$

3 step solution

Problem 75

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=x^{4}, \quad x \leq 0$$

3 step solution

Problem 75

Find two functions \(f\) and \(g\) such that \((f \circ g)(x)=h(x)\) (There are many correct answers.) $$h(x)=\frac{1}{x+2}$$

2 step solution

Problem 75

A rectangle is bounded by the \(x\) -axis and the semicircle \(y=\sqrt{36-x^{2}},\) as shown in the figure. Write the area \(A\) of the rectangle as a function of \(x\) and determine the domain of the function.

3 step solution

Problem 76

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=x^{2}, \quad x \geq 0$$

5 step solution

Problem 77

You can use either of two methods to graph a function: plotting points, or translating a parent function as shown in this section. Which method do you prefer to use for each function? Explain. $$\text { (a) } f(x)=3 x^{2}-4 x+1$$ $$\text { (b) } f(x)=2(x-1)^{2}-6$$

4 step solution

Problem 77

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=\sqrt{4-x^{2}}, \quad 0 \leq x \leq 2$$

4 step solution

Problem 77

Find two functions \(f\) and \(g\) such that \((f \circ g)(x)=h(x)\) (There are many correct answers.) $$h(x)=(x+4)^{2}+2(x+4)$$

3 step solution

Problem 77

A company produces a product for which the variable cost is \(\$ 68.75\) per unit and the fixed costs are \(\$ 248,000 .\) The product sells for \(\$ 99.99 .\) Let \(x\) be the number of units produced and sold. (a) The total cost for a business is the sum of the variable cost and the fixed costs. Write the total cost \(C\) as a function of the number of units produced. (b) Write the revenue \(R\) as a function of the number of units sold. (c) Write the profit \(P\) as a function of the number of units sold. (Note: \(P=R-C.)\) (d) Use the model in part (c) to find \(P(20,000) .\) Interpret your result in the context of the situation. (e) Use the model in part (c) to find \(P(0) .\) Interpret your result in the context of the situation.

5 step solution

Problem 78

The graph of \(y=f(x)\) passes through the points \((0,1),(1,2),\) and \((2,3) .\) Find the corresponding points on the graph of \(y=f(x+2)-1\).

2 step solution

Problem 78

Find the inverse function of \(f\) algebraically. Use a graphing utility to graph both \(f\) and \(f^{-1}\) in the same viewing window. Describe the relationship between the graphs. $$f(x)=\sqrt{16-x^{2}}, \quad-4 \leq x \leq 0$$

3 step solution

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