Question 43815
A rectangle is placed under the parabolic arch given by f(x)=27-3x^2 by using a point (x,y) on the parabola.  Write a formula for the function A(x) that gives the area of the rectangle as a function of the x-coordinate of the point chosen.  Ok so far this one has given me some trouble trying to work out.  Came up with answer of f(x)= 6(27-3x^2) it this right.

I assume you put this on a coordinate system; then chose a point (x,y)
on the parabola; then drew the rectangle symmetric to the y-axis.

The area of the rectangle = (2x)y
=2x(27-3x^2)
=54x-6x^3

Cheers,
Stan H.