Questions: What is the focus (are the foci) of the shape defined by the equation x^2/25 + y^2/9 = 1?
(0,2) and (0,-2)
(2,0) and (-2,0)
(4,3) and (-4,-3)
(4,0) and (-4,0)
(0,4) and (0,-4)
Transcript text: What is the focus (are the foci) of the shape defined by the equation $\frac{x^{2}}{25}+\frac{y^{2}}{9}=1$ ?
$(0,2)$ and $(0,-2)$
$(2,0)$ and $(-2,0)$
$(4,3)$ and $(-4,-3)$
$(4,0)$ and $(-4,0)$
$(0,4)$ and $(0,-4)$
Solution
Solution Steps
Step 1: Identify the Type of Conic Section
The given equation is
\[
\frac{x^{2}}{25} + \frac{y^{2}}{9} = 1
\]
This is the standard form of an ellipse, where \(\frac{x^2}{a^2} + \frac{y^2}{b^2} = 1\). Here, \(a^2 = 25\) and \(b^2 = 9\).
Step 2: Determine the Orientation of the Ellipse
Since \(a^2 > b^2\), the major axis is along the x-axis. Therefore, the ellipse is horizontally oriented.
Step 3: Calculate the Foci
For an ellipse, the distance from the center to each focus is given by \(c\), where \(c^2 = a^2 - b^2\).
Calculate \(c\):
\[
c^2 = a^2 - b^2 = 25 - 9 = 16
\]
\[
c = \sqrt{16} = 4
\]
The foci are located at \((\pm c, 0)\), which means the foci are at \((4, 0)\) and \((-4, 0)\).