The function y = - 1 / 2 (x-1) ² + 2, when x takes what value, y increases with the increase of X? When x takes what value, y decreases with the increase of X? What I learned in the first semester of junior three, if there is a calculation process, it's better to list it When x takes what value, Y > 0, y < 0?

The function y = - 1 / 2 (x-1) ² + 2, when x takes what value, y increases with the increase of X? When x takes what value, y decreases with the increase of X? What I learned in the first semester of junior three, if there is a calculation process, it's better to list it When x takes what value, Y > 0, y < 0?

Let x = X-1, then y = - 1 / 2x ^ 2 + 2
When x > 0, y increases with the increase of X, then x = X-1 > 0, that is, x > 1
When x