Answer: 800 feet²
Step-by-step explanation:
Lets remove the brackets from the function's expression
A(x) = -2x²+80x
So we got the quadratic function and we have to find the x that corresponds to function's maximum. Let it be X max
As we know Xmax= (X1+X2)/2 , where X1 and X2 are the roots of the function A(x)
Lets find X1 and X2
x(80-2x)=0
x1=0 80-2*X2=0
x2=40
So Xmax= (0+40)/2=20
So Amax= A(20)= 20*(80-2*20)=20*40=800 feet²
Polar and cartesian equation<h2>Initial explanation</h2>
Let's analyze the relation between r and x and y:
We have that between the indicated value of r (of the polar coordinates) and x and y (of the cartesian coordinates) there is a relation because they form a triangle. If r changes, then the value of x and y will change.
<h2>STEP 1: given equation</h2>
Using the given equation
r = 2 secØ
we have that

<h2>STEP 2: secØ equation</h2>
Observing the image of the initial explanation we have a right triangle, we know that the equation of
secØ for any right triangle is given by:

In this case,
hypotenuse = r
adjacent side = x
then,

<h2>STEP 3: comparison between given equation and secØ equation</h2>
Then, we have that:

This means that:

Then,
x = 2
The equation in cartesian coordinates is x=2.
Answer: x=2
Answer:


Step-by-step explanation:
We have been given that at a zoo, the lion pen has a ring-shaped sidewalk around it. The outer edge of the sidewalk is a circle with a radius of 11 m. The inner edge of the sidewalk is a circle with a radius of 9 m.
To find the area of the side walk we will subtract the area of inner edge of the side walk of lion pen from the area of the outer edge of the lion pen.
, where r represents radius of the circle.



Therefore, the exact area of the side walk is 
To find the approximate area of side walk let us substitute pi equals 3.14.


Therefore, the approximate area of the side walk is
.