Question

Help with 3 Calculus Problems? (Related Rates)

Answer 1

1). At a sand and gravel plant, sand is falling off a conveyor and onto a conical pile at the rate of 13 cubic feet/min. The diameter of the base of the cone is approximately three times the altitude. At what rate is the height of the pile changing when it is 15 ft high? Answer in units of ft/min
- I got 52/2025*pi or 0.08067299653

This one has two parts to it.

Assume that x and y are both differentiable functions of t and xy=4
a). Find dy/dt when x=7.8 and dx/dt=10.5
- for this part, I got -.690
b). Find dx/dt when x=1.3 and dy/dt=-6.4
- for this part, I got 2.703

If someone could corroborate with my answers, and, if I'm wrong, possibly correct me, that would be great! Also, please include as many decimal places as you can, because this is online homework and it sometimes marks the answers wrong if there aren't enough decimal places. Also, I want work so I can compare with you and see if I did something incorrectly.