I want to compute this area with a condition : y>=1. Is it possible?
The regions can be visualized as follows:
RegionPlot[{y > x^2, y < 8 - x^2, y > x + 2, y > 1}, {x, -5, 5}, {y, -5, 15}]
Now you can rewrite it and choose the > and < symbols correctly:
RegionPlot[y > x^2 \[And] y < 8 - x^2 \[And] y > x + 2 \[And] y > 1, {x, -5, 5}, {y, -5, 15}]
Once you know that go ahead and integrate the area:
Integrate[Boole[y > x^2 \[And] y < 8 - x^2 \[And] y > x + 2 \[And] y > 1], {x, -5, 5}, {y, -5, 15}]
Thank you very much!
Note that the y>1 doesn’t do anything…