②
The cardinality is greater than 1, so y = 2 x is the increasing function, that is, the increasing interval of the y function.
y=? -x? +x+2 is a parabola with an axis of symmetry x= 1/2 and a downward opening, so it increases when x≤ 1/2 and x >; Decreasing by 1/2
Therefore, the increasing interval of the function F(x) is (-∞, 1/2], and the decreasing interval is (1/2,+∞).
③
From the meaning of the question, we can know that x 2-x-6 ≥ 0, that is, (x-3)(x+2)≥0, and the solution is x≥3. x≤-2
The symmetry axis of function f (x) = x 2-x-6 x= 1/2, the opening is upward, x < = 1/2, the function f (x) decreases, x >;; The function f(x) of 1/2 increases.
Therefore, the increasing interval of y = √ (x 2-x-6) is [3, +∞), and the decreasing interval is (-∞, -2].
④
2-x 2 ≥ 0, that is, -√2≤? x? ≤√2
The symmetry axis of the image with y = 2-x 2 is x=0, the opening is downward, and x >;; =0 decreasing, x
So f (√ 2-x 2) decreasing interval? [0,√2]