Which of the following equations is of an ellipse with x-intercepts at (1, 0) and (-1, 0), y-intercepts at (0, 3) and (0, -3), and center at (0, 0)?
a.) x^2/1 + y^2/9 =1
b.) x^2/1 - y^2/9 =1
c.) x^2/9 + y^2/1 =1
If you were to plot the x and y intercepts you would see that this will be a vertical ellipses, taller that it is wider. The formula for an ellipse is [tex] \frac{ x^{2} }{b^2} + \frac{y^2}{a^2}=1 [/tex]. The "a" value is always the bigger value of the a and b. The bigger value, the a, will always go under the variable that is the major axis. The major axis for us is the y axis. a = 3, so 3 squared is 9. b = 1 and 1 squared is 1. So our equation will be [tex] \frac{x^2}{1}+ \frac{y^2}{9}=1 [/tex], choice a from above.
