Hello, Gracy,

you have the graphs of 2 functions:

and

The enclosed area is calculated by the difference of these two functions:

Calculate the zeros of u. These zeros correspond with the intercepts of l and f. You'll get: x = -1 or x = 0 or x = 1

For symmetry reasons the area can be calculated as:

I've got A=0.5

I've attached a sketch of the enclosed area.

EB