Answer:
Step-by-step explanation:
The volume for a cone is
Let's look at the derivative of this to see what we need to fill into it against what we were given to fill into it. The derivative of the volume with respect to time is
If this is the formula we are to use, we need a radius measure (we have one), a dr/dt (we don't have one), a height (we seem to have 2 of those!), and we are ultimately looking for dh/dt.
Because of the fact that we do not have a dr/dt value along with the fact that we have 2 values of height, we have to find a rewrite for that volume formula where the radius is in terms of the height. That way we don't need to worry about the rate of change of radius (becasue we weren't given one anyway!). The reason we were given that the height of the cone is 10 and the radius is 2 is so we can write the radius in terms of the height. Use proportions to do this:
Cross multiply to get 10r = 2h so
We will now be able to express the volume in terms of height only:
which simplifies down to
This is what we will take the derivative of.
The 3's cancel, leaving a little bit of a simpler formula:
We were given that dV/dt = 2 and we are to find dh/dt when h = 6. Filling in what we given then:
or
Multiply by the reciprocal of the fraction on the right and simplify to
or, in decimal form .4420970641in/sec
The last line of a proof represents the conclusion.
8*10=80 pages in one hour
Answer:
C (-2, 0)
Step-by-step explanation:
y = x+2
intersect the x-axis when y = 0, then
0 = x+2
x = -2
Answer:
9 : 10
Step-by-step explanation:
First the ratio will be 63 : 70
Now, we have to simplify! The GCF (greatest common factor) is 7, so let's divide both numbers by 7 to maintain equality.
63/7 = 9
70/7 = 10
9 : 10 is the final answer!