96b520aec5aaa1bed088249388dc506dc601cb80
1\definecolor{shade1}{HTML}{ffffff}
2\definecolor{shade2}{HTML}{e6f2ff}
3\definecolor{shade3}{HTML}{cce2ff}
4\section{Transformations}
5
6\textbf{Order of operations:} DRT
7
8\begin{center}dilations --- reflections --- translations\end{center}
9
10\subsection*{Transforming \(x^n\) to \(a(x-h)^n+K\)}
11
12\begin{itemize}
13\tightlist
14\item
15 dilation factor of \(|a|\) units parallel to \(y\)-axis or from
16 \(x\)-axis
17\item
18 if \(a<0\), graph is reflected over \(x\)-axis
19\item
20 translation of \(k\) units \(\parallel y\)-axis/from \(x\)-axis
21\item
22 translation of \(h\) units \(\parallel x\)-axis/from \(y\)-axis
23\item
24 for \((ax)^n\), dilation factor is \(1 \over a \> \parallel x\)-axis/from \(y\)-axis
25\item
26 when \(0 < |a| < 1\), graph becomes closer to axis
27\end{itemize}
28
29\subsection*{Transforming \(f(x)\) to \(y=Af[n(x+c)]+b\)}
30
31Applies to exponential, log, trig, \(e^x\), polynomials.\\
32Functions must be written in form \(y=Af[n(x+c)]+b\)
33
34\begin{itemize}
35\tightlist
36\item
37 dilation by factor \(|A|\) from \(x\)-axis (if \(A<0\), reflection
38 across \(y\)-axis)
39\item
40 dilation by factor \(1 \over n\) from \(y\)-axis (if \(n<0\),
41 reflection across \(x\)-axis)
42\item
43 translation of \(c\) units from \(y\)-axis (\(x\)-shift)
44\item
45 translation of \(b\) units from \(x\)-axis (\(y\)-shift)
46\end{itemize}
47
48\subsection*{Dilations}
49
50Two pairs of equivalent processes for \(y=f(x)\):
51
52\begin{enumerate}
53\def\labelenumi{\arabic{enumi}.}
54\item
55 \begin{itemize}
56 \tightlist
57 \item
58 Dilating from \(x\)-axis: \((x, y) \rightarrow (x, by)\)
59 \item
60 Replacing \(y\) with \(y \over b\) to obtain \(y = b f(x)\)
61 \end{itemize}
62\item
63 \begin{itemize}
64 \tightlist
65 \item
66 Dilating from \(y\)-axis: \((x, y) \rightarrow (ax, y)\)
67 \item
68 Replacing \(x\) with \(x \over a\) to obtain \(y = f({x \over a})\)
69 \end{itemize}
70\end{enumerate}
71
72For graph of \(y={1 \over x}\), horizontal \& vertical dilations are
73equivalent (symmetrical). If \(y={a \over x}\), graph is contracted
74rather than dilated.
75
76\subsection*{Matrix transformations}
77
78Find new point \((x^\prime, y^\prime)\). Substitute these into original
79equation to find image with original variables \((x, y)\).
80
81\subsection*{Reflections}
82
83\begin{itemize}
84\tightlist
85\item
86 Reflection \textbf{in} axis = reflection \textbf{over} axis =
87 reflection \textbf{across} axis
88\item
89 Translations do not change
90\end{itemize}
91
92\subsection*{Translations}
93
94For \(y = f(x)\), these processes are equivalent:
95
96\begin{itemize}
97\tightlist
98\item
99 applying the translation \((x, y) \rightarrow (x + h, y + k)\) to the
100 graph of \(y = f(x)\)
101\item
102 replacing \(x\) with \(x-h\) and \(y\) with \(y-k\) to obtain
103 \(y-k = f(x-h)\)
104\end{itemize}
105
106\subsection*{Power functions}
107
108Mostly only on CAS.
109
110We can write
111\(x^{-1 \over n} = {1 \over {x^{1 \over n}}} = {1 \over ^n \sqrt{x}}\)n.\\
112Domain is:
113\(\begin{cases} \mathbb{R} \setminus \{0\}\hspace{0.5em} \text{ if }n\text{ is odd} \\ \mathbb{R}^+ \hspace{2.6em}\text{if }n\text{ is even}\end{cases}\)
114
115If \(n\) is odd, it is an odd function.
116
117\subsubsection*{\(x^{p \over q}\) where \(p, q \in \mathbb{Z}^+\)}
118
119\[x^{p \over q} = \sqrt[q]{x^p}\]
120
121\begin{itemize}
122\tightlist
123\item
124 if \(p > q\), the shape of \(x^p\) is dominant
125\item
126 if \(p < q\), the shape of \(x^{1 \over q}\) is dominant
127\item
128 points \((0, 0)\) and \((1, 1)\) will always lie on graph
129\item
130 Domain is:
131 \(\begin{cases} \mathbb{R} \hspace{4em}\text{ if }q\text{ is odd} \\ \mathbb{R}^+ \cup \{0\} \hspace{1em}\text{if }q\text{ is even}\end{cases}\)
132\end{itemize}
133