Calculus: Applications of Derivatives

[ohhoneyy]

I got confused.

But yahoo answers have people like you too!
LOL..

[jchuu]

Vf - Vi = 80 000 - 180 000

[sw33tsmil3s]

I think the negative is direction of wateR? LOL not sure

This is what I did:

[S(10) - S(0)] / (10-0) = [200(20)^2 - 200(30)^2] / 10 = -10,000

[ohhoneyy]

^ yeah I get it now, negative because wter is decresing.

[Monster]

^ It's negative because the water is flowing out.

Edit: ohhoneyy beat me to it.

[jchuu]

How fast is the water running at the end of 10min? vinstant = -7 999.8 gallons/min
Vinst = lim(t->0) [f(a + t) - f(a)]/t = lim(t->0) [f(10 + 0.001) - f(10)]/0.001 ......... then just do math

[sw33tsmil3s]

2nd Question now:) (the one on the horse and furlongs)

[air23]

Don't know if you got it yet, but I think Equilateral triangle Area should be (square root 3 s^2 )4 and not cube root?

If you look at half of the equilateral triangle as a right triangle, you'll have the height, 's' as a side of the equilateral triangle and s/2 on the bottom.

then Pythagorean theorem should give you h^2 = s^2 - (s/2)^2
do some algebra and you'll have h = (square root 3 *s)/2
plug it into A = s * h *1/2 (triangle area) and you should get
A = (square root 3 * s^2)/4

[*pinkpeachz]

you guys are giving me a headache ><

[jchuu]

c) What is the approximate speed of the horse as it passes the 3-furlong marker? 16.9 yards/s, 220yards/13s
d) During which portion of the race is the horse running the fastest? between F9-F10, v=20yards/s
e) accelerating the fastest? F1-F2, calc velocity at each second, you would see that greatest Δv
is +5.9y/s^2