Questions: Write an equation for the function graphed below. The y intercept is at (0,-0.5) y=
Transcript text: Write an equation for the function graphed below. The $y$ intercept is at $(0,-0,5)$
\[
y=
\]
Solution
Write an equation for the function graphed below. The \(y\) intercept is at \((0,-0.5)\).
Find the vertical asymptotes.
The vertical asymptotes are at \(x=-1\) and \(x=2\). Thus, the denominator must have factors \((x+1)\) and \((x-2)\).
Find the horizontal asymptote.
The horizontal asymptote is \(y=0\), which means the degree of the numerator is less than the degree of the denominator.
Find the \(x\) intercepts.
The \(x\) intercept is at \(x=1\), so the numerator must have a factor of \((x-1)\).
Find the \(y\) intercept.
The \(y\) intercept is at \((0,-0.5)\).
Construct the equation.
Let the equation be
\[
y = \frac{a(x-1)}{(x+1)(x-2)}
\]
Substitute \(x=0\) and \(y=-0.5\):
\[
-0.5 = \frac{a(0-1)}{(0+1)(0-2)}
\]
\[
-0.5 = \frac{-a}{-2}
\]
\[
-0.5 = \frac{a}{2}
\]
\[
a = -1
\]
Therefore, the equation is
\[
y = \frac{-(x-1)}{(x+1)(x-2)} = \frac{1-x}{(x+1)(x-2)} = \frac{1-x}{x^2-x-2}
\]