1. The problem statement, all variables and given/known data I have attached a link along with my working please can someone help me http://s359.photobucket.com/albums/oo40/jsmith613/?action=view¤t=Math.png 2. Relevant equations 3. The attempt at a solution
Please post the problem and your work here. IMO, it's a pain in the butt to have to open a web page to see the problem and the work, plus I can't insert a comment at the appropriate place where there's an error.
dv/dt = 4 cm^{3} min^{-1} tan(60) = r/h r = √3* h V = (1/3) π r^{2}h dv/dh = (1/3) π r^{2} dh/dt = (dh/dv) * (dv/dt) = ^{1}/_{(1/3) π r2} * 4 = 12/(pi r^{2}) for h = 4 dh/dt = 0.079577 The answer given is 0.0265 cm/min. why? I don't know how do use latex - see post for a clearer solution if you get lost!
question was: A hollow cone with a semi-vertical angle of 60 degrees is held vertex down with its axis vertical. Water drips into the cone at 4 cm^{3}/min Find the rate at which the depth of water is increasing when the water is 4 cm deep
You're ignoring the relationship between r and h. Substitute for r in your volume equation. Then you'll have V purely as a function of h. What you have is not correct, because V is a function of r and h.