What are the foci of the ellipse given by the equation 100x2 + 64y2 = 64,000?
a. (0, ±6)
b. (±6, 0)
c. (0, ±36)
d. (±36, 0)

Question

What are the foci of the ellipse given by the equation 100x2 + 64y2 = 64,000?
a. (0, ±6)
b. (±6, 0)
c. (0, ±36)
d. (±36, 0)

anonymous · Answer

@Zelda ?

anonymous · Answer

@howdomath, no idea mate. I don't remember this at all...

anonymous · Answer

Ah ok, thanks anyway. You may not remember this either because they're in the same unit I guess but I'll ask:
A parabolic microphone has a cross-section in the shape of a parabola. The microphone is placed at the focus of the parabola. If the parabola is 20 inches wide and 5 inches deep, how far from the vertex should the microphone be placed? 
a. 4 inches
b. 5 inches
c. 8 inches
d. 10 inches

anonymous · Answer

5 inches