Help On Ap Calc Hw
if a snowball melts so that it surface area decreases at a rate of 1 cm^2/min, find the rate at which the diameter decreases when the diameter is 10 cm.
i get -1/40pi (it decreases)
thx flamedagger! also i need help on this one. http://www.basilmarket.com/forum/2532304
October 22, 2012
10 Comments • Newest first
[quote=Vanta]Man I always hated these types of problems... Except my calculus teacher gave us problems like "Gravel is being unloaded from a truck in the shape of a cone at ... cm^3/sec."
It will get much worse by the way. I took AP Calculus last year in high school and this year in college I feel like all of that was extremely basic material.[/quote]
that's one my problems too lol, but it was odd so i could check my answer
[quote=Vanta]Man I always hated these types of problems... Except my calculus teacher gave us problems like "Gravel is being unloaded from a truck in the shape of a cone at ... cm^3/sec."
It will get much worse by the way. I took AP Calculus last year in high school and this year in college I feel like all of that was extremely basic material.[/quote]
I found my 1st year calc wasn't that much worse then my high school non-AP calculus.
[quote=flamedagger]No, using chain rule, (D/2)^2 is D/2[/quote]
o yeh forgot that my way only worked for x^2, thx!
No, using chain rule, (D/2)^2 is D/2
[quote=flamedagger]A=4pi(D/2)^2
find dD/dt.
dA/dt= 4pi(D/2)dD/dt
-1=4pi(10/2)dD/dt
-1=20pi dD/dt
dD/dt= -1/20pi[/quote]
derivative of (D/2)^2 is D tho
[quote=flamedagger]khanacademy is good for everything [/quote]
If only it was more known and people had motivation to learn... I know so much people who fail and don't intend to improve..
khanacademy is good for everything
yeah, you might have forgotten the chain rule in applying the (D/2) so maybe that's where you're off by 1/2
I'm surprised your actually asking basili on this... Shouldn't you be using your textbook? .__.
A=4pi(D/2)^2
find dD/dt.
dA/dt= 4pi(D/2)dD/dt
-1=4pi(10/2)dD/dt
-1=20pi dD/dt
dD/dt= -1/20pi