Which is the equation of an ellipse centered at the origin with foci on y-axis, x-intercepts +1 and y-intercepts +8?
a.
C.
2
64
y?
x²
64
*
= 1
1
b.
d.
+
= 1
y?
1 64
Please select the best answer from the choices provided
A
B
C
Save and Exit
Nex

8

Step-by-step explanation:

0) the basic formula is: L=v*t, where L - distance, v - speed/velocity; t - time;

1) if the person's speed in still water is 'v' and the speed of water is 5 (according to the condition), then the upstream speed is 'v-5' and the downstream speed is 'v+5';

2) according to the condition the upstream time and the downstream time are the same, it means t₁=t₂=t, where t₁=upstream time and t₂=downstream time;

3) according to the items above it is possible to make up the equation of the upstream travel: t(v-5)=3; ⇒ t=3/(v-5);

4) according to the items above it is possible to make up the equation of the downstream travel: t(v+5)=13; ⇒ t=13/(v+5);

5) if t=3/(v-5) and t=13/(v+5), then