Find the area of bounded by f(x)=2x^2

and g(x)=x^4-2x^2

It is easy to solve for their intersections.

I got x=0 , x= ± 2

Doing a rough sketch will show that there are 2 symmetrical regions, so let's do the one from 0 to 2
the height of the region is 2x^2 - (x^4 - 2x^2)
= 4x^2 - x^4

so the area of that region is the integral of the above from 0 to 2

= (4/3)x^3 - (1/5)x^5 │ from 0 to 2
= 32/3 - 32/5
= 64/15

the region on the left side of the y-axis is equal to that, so that the total area is

128/15

(check my arithmetic, I'm only on my first coffee)