Afarmer has 1,200 feet of fencing and wants to fence off a rectangular field that borders a straight river. he needs no fence along the river. write the function that will produce the largest area if x is the short side of the rectangle.

f(x) = 1200x − x2
my answer choice. is this correct? -> f(x) = −2x2 + 1200x
f(x) = x2 − 1200
f(x) = 2x2 − 1200

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

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square