The minimum value of the function f (x) = the square of X + ax + 3 in [0,1] is

The minimum value of the function f (x) = the square of X + ax + 3 in [0,1] is

The minimum value of function f (x) = x ^ 2 + ax + 3 on [0,1] is
1. When the axis of symmetry x = - (A / 2) is on the left side of the interval [0,1], that is, when a > 0, the minimum value of the function at the left end of the interval is f (0) = 3
2. The axis of symmetry x = - (A / 2) is on the right side of the interval [0,1], i.e. a

Find the value range of a whose value range of function y = x ^ 2 + AX-2 / x ^ 2-x + 1 is (- ∝, 2)

Because the denominator = x ^ 2-x + 1 = (x-1 / 2) ^ 2 + 3 / 4, we know that the definition field of the function is r, and the denominator is always positive. We also know that for any real number x, there is always f (x) - 20 = = = > from the denominator is always greater than 0, we get that for any real number x, there is always x ^ 2 - (a + 2) x + 4 > 0 = = = = = > (a + 2) ^ 2-16-6

The range of y = cos x + 4sinx-2

y=cos x+4sinx-2
=√17（1/√17cosx+4/√17sinx）-2
Let cos ξ = 1 / 17, sin ξ = 4 / 17,
Then y = √ 17cos (x - ξ) - 2,
Because - 1 ≤ cos (x - ξ) ≤ 1,
So - √ 17-2 ≤ y ≤ √ 17-2