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Exercises 4.3 Practice Problems
1.
Suppose
\(f(x) = 2x+1\text{.}\)
Evaluate each of the following:
-
\(\displaystyle f^{-1}(0)\)
-
\(\displaystyle f^{-1}(4)\)
-
\(\displaystyle f^{-1}(9)\)
-
\(\displaystyle f^{-1}(1)\)
-
\(\displaystyle f^{-1}(10)\)
Answer.
-
\(\displaystyle f^{-1}(0)=\frac{-1}{2}\)
-
\(\displaystyle f^{-1}(4)=\frac{3}{2}\)
-
\(\displaystyle f^{-1}(9)=4\)
-
\(\displaystyle f^{-1}(1)=0\)
-
\(\displaystyle f^{-1}(10)=\frac{9}{2}\)
2.
Suppose
\(f(x) = 3x-2\text{.}\)
Evaluate each of the following:
-
\(\displaystyle f^{-1}(1)\)
-
\(\displaystyle f^{-1}(3)\)
-
\(\displaystyle f^{-1}(0)\)
-
\(\displaystyle f^{-1}(5)\)
-
\(\displaystyle f^{-1}(4)\)
Answer.
-
\(\displaystyle f^{-1}(1)=1\)
-
\(\displaystyle f^{-1}(3)=\frac{5}{3}\)
-
\(\displaystyle f^{-1}(0)=\frac{2}{3}\)
-
\(\displaystyle f^{-1}(5)=\frac{7}{3}\)
-
\(\displaystyle f^{-1}(4)=2\)
3.
Suppose
\(f(x)\) is given in the graph below.
Evaluate each of the following:
-
\(\displaystyle f^{-1}(0)\)
-
\(\displaystyle f^{-1}(1)\)
-
\(\displaystyle f^{-1}(9)\)
-
\(\displaystyle f^{-1}(2)\)
-
\(\displaystyle f^{-1}(4)\)
Answer.
-
\(\displaystyle f^{-1}(0)=1\)
-
\(\displaystyle f^{-1}(1)=2\)
-
\(\displaystyle f^{-1}(9)=5\)
-
\(\displaystyle f^{-1}(2)=3\)
-
\(\displaystyle f^{-1}(4)=4\)
4.
Suppose
\(g(x)\) is given in the table below.
Table 4.3.1.
\(x\) |
\(-1\) |
\(3\) |
\(2\) |
\(5\) |
\(4\) |
\(g(x)\) |
\(0\) |
\(3\) |
\(7\) |
\(1\) |
\(2\) |
Evaluate each of the following:
-
\(\displaystyle g^{-1}(0)\)
-
\(\displaystyle g^{-1}(1)\)
-
\(\displaystyle g^{-1}(3)\)
-
\(\displaystyle g^{-1}(7)\)
-
\(\displaystyle g^{-1}(2)\)
Answer.
-
\(\displaystyle g^{-1}(0)=-1\)
-
\(\displaystyle g^{-1}(1)=5\)
-
\(\displaystyle g^{-1}(3)=3\)
-
\(\displaystyle g^{-1}(7)=2\)
-
\(\displaystyle g^{-1}(2)=4\)
5.
Suppose
\(g(x)\) is given in the table below.
Table 4.3.2.
\(x\) |
\(0\) |
\(2\) |
\(3\) |
\(5\) |
\(4\) |
\(g(x)\) |
\(0\) |
\(1\) |
\(7\) |
\(5\) |
\(2\) |
Evaluate each of the following:
-
\(\displaystyle g^{-1}(0)\)
-
\(\displaystyle g^{-1}(1)\)
-
\(\displaystyle g^{-1}(2)\)
-
\(\displaystyle g^{-1}(7)\)
-
\(\displaystyle g^{-1}(5)\)
Answer.
-
\(\displaystyle g^{-1}(0)=0\)
-
\(\displaystyle g^{-1}(1)=2\)
-
\(\displaystyle g^{-1}(2)=4\)
-
\(\displaystyle g^{-1}(7)=3\)
-
\(\displaystyle g^{-1}(5)=5\)
6.
Find a formula for the inverse.
Answer.
\(f^{-1}(x)=\frac{x-7}{5}\)
7.
Suppose
\(g(x) = \frac{x+3}{2x-4}\text{.}\)
Find a formula for the inverse.
Answer.
\(g^{-1}(x)=\frac{3+4x}{2x-1}\)
8.
Suppose
\(f(x) = x^3 -3\text{.}\)
Find a formula for the inverse.
Answer.
\(f^{-1}(x)=\sqrt[3]{x+3}\)
9.
Suppose
\(g(x) = \frac{2x+3}{5x-4}\text{.}\)
Find a formula for the inverse.
Answer.
\(g^{-1}(x)=\frac{3+4x}{5x-2}\)
10.
Suppose
\(g(x) = (x+1)^5\text{.}\)
Find a formula for the inverse.
Answer.
\(g^{-1}(x)=\sqrt[5]{x}-1 \)
11.
Suppose
\(g(x) = \frac{2}{7x-3}\text{.}\)
Find a formula for the inverse.
Answer.
\(g^{-1}(x)=\frac{2+3x}{7x}\)
12.
Suppose
\(g(x) = \sqrt[7](x) + 8\text{.}\)
Find a formula for the inverse.