Answer:
78
Step-by-step explanation:
you multiply
Answer:
Step-by-step explanation:
I am assuming the tank starts empty. It means that in 1 hour the tank has half that water, or 3600 gallons. And the good thing of lines passing through 0.0 is that the value at 1 IS the slope we need. ie 3600.
At this point it's easy to find that if in 2 hours it filled 1/10th of the tank, in 20 hours the tank will be full.
Graph done with paint, obviously not to scale.
Yay, derivitives
I'mma ignore that x is the shorter side because I don't know which one has to be shorter yet
we need to find the max area
but with 3 sides
area=LW
let's say the sides are z and y
zy=area
and the relatiionship between them is
hmm,
z+2y=1200
because one side has no fencing
so
z+2y=1200
solve for z
z=1200-2y
sub for z in other
(1200-2y)(y)=area
expand
1200y-2y²=area
take derivitive
1200-4y=dy/dx area
max is where dy/dx goes from positive to negative
solve for where dy/dx=0
1200-4y=0
1200=4y
300=y
at y<300, dy/dx<0
at y>300, dy/dx>0
so at y=300, that is the max
then
z=1200-2y
z=1200-2(300)
z=1200-600
z=600
so then
z=600
y=300
300<600
so the shorter side would be y
so then we see our choices and noticed that
erm
I think it is f(x)=1200x-2x²
takind the derivitive yeilds none of the others
so ya, you are right
