SOLUTION: A rectangle is bounded by the x-axis and the semicircle y=[36-x^2]square root. Write the area of the rectangle as a function of x, and determine the domain of the function

Algebra ->  Functions -> SOLUTION: A rectangle is bounded by the x-axis and the semicircle y=[36-x^2]square root. Write the area of the rectangle as a function of x, and determine the domain of the function      Log On


   



Question 162453: A rectangle is bounded by the x-axis and the semicircle y=[36-x^2]square root. Write the area of the rectangle as a function of x, and determine the domain of the function.
This is the picture of the graph: http://hmco.tdlc.com/pre3e/common/ch30/ch30c/30c_images/2901087.gif

Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
A rectangle is bounded by the x-axis and the semicircle y=sqrt%2836-x%5E2%29. Write the area of the rectangle as a function of x, and determine the domain of the function.
This is the picture of the graph: http://hmco.tdlc.com/pre3e/common/ch30/ch30c/30c_images/2901087.gif

Label the upper right hand corner of the
rectangle (x,y):



Now if we just look at the right half of that
rectangle, we have:



The area of the right half of the rectangle
is base%2Aheight=xy.

Therefore the area of the entire rectangle:



is twice that or 

A+=+2xy.

However, that is the area in terms of both
x and y.  

We must get the area A in terms of just x.

So we replace y in A+=+2xy by y=sqrt%2836-x%5E2%29

A=2x%2Asqrt%2836-x%5E2%29

Your teacher may want you to write A%28x%29 instead of A

If so the answer in functional notation is: 

A%28x%29=2x%2Asqrt%2836-x%5E2%29

Edwin