My Math Forum  

Go Back   My Math Forum > College Math Forum > Calculus

Calculus Calculus Math Forum

LinkBack Thread Tools Display Modes
January 17th, 2008, 12:59 PM   #1
Joined: Jan 2008

Posts: 2
Thanks: 0

Related Rates Problem Please Help!!!

Can anyone help me out with these questions? I'm so lost in this unit... lol

I have 3 questions left and I really need help on them.

Water runs into a tank that is in the shape of an inverted cone at the rate of 9cubic feet/min. The tank has a height of 10 ft and a base radius of 5 ft. How fast is the water level rising when the water is 4 ft deep?

The length of the base of a right triangle is increasing at the rate of 12in/min. At the same time, the height of the triangle is decreasing in such a way that the length of the hypotenuse remains 10 inches. How quickly is the height of the triangle changing when the length of the base is 6 inches?

A spherical balloon is being inflated so that its volume is increasing at the rate of 5 cubic meters/min. At what rate is the diameter increasing when the diameter is 12m? (V = 4/3(pi)r^3)

Thanks in advance!
noselord is offline  
January 17th, 2008, 01:24 PM   #2
Joined: Jan 2008

Posts: 1
Thanks: 0

Dude it doesn't help you if I just give you the answer. I will give you a hint For the 1st question use similar triangles. For the 2nd use pythagorem theorm then take the derivitive respect to dt. dx/dt would be 12in/min . You have the formula for the last one you probably need to write equation interms of d.. subsitute d/2=r. (pi(d)^2)/2(dd/dt)=dv/dt substitute dv/dt= 5m^3/min then solve for dd/dt
student12 is offline  
January 17th, 2008, 04:29 PM   #3
Joined: Jan 2008

Posts: 2
Thanks: 0

ok nvm i think i got the answers

could u double check please?

In order

1) 9/4(pi)
2) -3/4
3) 5(pi) / 72
noselord is offline  
January 18th, 2008, 03:57 AM   #4
Global Moderator
Joined: Dec 2006

Posts: 19,059
Thanks: 1619

You've made some errors; please post you're working.
skipjack is offline  

  My Math Forum > College Math Forum > Calculus

problem, rates, related

Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Another Related Rates Problem Shamieh Calculus 5 October 8th, 2013 06:58 PM
related rates problem jamjam19 Calculus 2 June 14th, 2013 09:32 AM
NEW Related Rates Problem mathkid Calculus 7 November 12th, 2012 11:53 AM
related rates problem fran1942 Calculus 3 April 30th, 2012 10:18 PM
related rates problem sivela Calculus 3 April 11th, 2010 11:56 AM

Copyright © 2018 My Math Forum. All rights reserved.