The ordinate of a is eight tenths of a, and the ordinate of b is four tenths of a.

So the equation with straight line ob is two squares of y =.

According to the distance formula, the distance from point A to straight line ob can be calculated as the fourth power of d = 6a/A +4.

The length of ob is h=2/a times a +4 to the fourth power.

So the area of aob is 1/2dh=6.

Of course, this is calculated by the method of senior two, I hope you can understand.