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Suppose that the functions [tex]\( p \)[/tex] and [tex]\( q \)[/tex] are defined as follows.

[tex]\[
\begin{array}{l}
p(x)=x^2+7 \\
q(x)=\sqrt{x+8}
\end{array}
\][/tex]

Find the following.

[tex]\[
\begin{array}{l}
(p \circ q)(1)= \\
(q \circ p)(1)=
\end{array}
\][/tex]


Sagot :

Certainly! Let's find the compositions [tex]\((p \circ q)(1)\)[/tex] and [tex]\((q \circ p)(1)\)[/tex] step by step.

### Finding [tex]\((p \circ q)(1)\)[/tex]

1. Understand what [tex]\((p \circ q)(1)\)[/tex] means: It represents the function [tex]\(p\)[/tex] applied to the result of the function [tex]\(q\)[/tex] evaluated at [tex]\(1\)[/tex]. In other words, [tex]\(p(q(1))\)[/tex].

2. Evaluate [tex]\(q(1)\)[/tex]:
[tex]\[ q(x) = \sqrt{x + 8} \][/tex]
Substitute [tex]\(x = 1\)[/tex]:
[tex]\[ q(1) = \sqrt{1 + 8} = \sqrt{9} = 3 \][/tex]

3. Now evaluate [tex]\(p(3)\)[/tex]:
[tex]\[ p(x) = x^2 + 7 \][/tex]
Substitute [tex]\(x = 3\)[/tex]:
[tex]\[ p(3) = 3^2 + 7 = 9 + 7 = 16 \][/tex]

Thus, [tex]\((p \circ q)(1) = 16\)[/tex].

### Finding [tex]\((q \circ p)(1)\)[/tex]

1. Understand what [tex]\((q \circ p)(1)\)[/tex] means: It represents the function [tex]\(q\)[/tex] applied to the result of the function [tex]\(p\)[/tex] evaluated at [tex]\(1\)[/tex]. In other words, [tex]\(q(p(1))\)[/tex].

2. Evaluate [tex]\(p(1)\)[/tex]:
[tex]\[ p(x) = x^2 + 7 \][/tex]
Substitute [tex]\(x = 1\)[/tex]:
[tex]\[ p(1) = 1^2 + 7 = 1 + 7 = 8 \][/tex]

3. Now evaluate [tex]\(q(8)\)[/tex]:
[tex]\[ q(x) = \sqrt{x + 8} \][/tex]
Substitute [tex]\(x = 8\)[/tex]:
[tex]\[ q(8) = \sqrt{8 + 8} = \sqrt{16} = 4 \][/tex]

Thus, [tex]\((q \circ p)(1) = 4\)[/tex].

### Summary

- [tex]\((p \circ q)(1) = 16\)[/tex]
- [tex]\((q \circ p)(1) = 4\)[/tex]

So the final results are:
[tex]\[ \begin{array}{l} (p \circ q)(1)= 16 \\ (q \circ p)(1)= 4 \end{array} \][/tex]