Given that f (x) = x square + ax-a, if x belongs to [- 2,2], f (x) is equal to or greater than 0, the value range of a is obtained

Given that f (x) = x square + ax-a, if x belongs to [- 2,2], f (x) is equal to or greater than 0, the value range of a is obtained

If f (x) = x & # 178; + ax-a ≥ 0, X belongs to [- 2,2] and the opening of the parabola is upward (1) if the parabola is all above or on the X axis, it must be suitable, that is, if Δ = A & # 178; + 4A ≤ 0, then - 4 ≤ a ≤ 0 (2) if there is an image below the X axis, the position of the symmetry axis should be discussed

Given the function f (x) = x & # 178; - 2aX + 4, the maximum value is obtained when x belongs to [1,2]
High school mathematics process detailed point oh!

If the function f (x) = x * x-2ax + 1 has a zero point in the interval (0,1) and (1,3), the value range of a is obtained

F (x) = x * x-2ax + 1 has a zero point on the interval (0,1) and (1,3) respectively
Then f (0) * f (1) < 0, and f (1) * f (3) < 0
F (0) = 0 * 0-2a * 0 + 1 > 0
Moreover, f (1) = 1 * 1-2a * 1 + 1 < 0, and f (3) = 3 * 3-2a * 3 + 1 > 0
And - 6A + 10 > 0
A > 1, and a < 5 / 3
∴1＜a＜5/3

The opening direction, symmetry axis and vertex coordinates of parabola y = - 2x2-5x + 7 are determined by formula

Y = - 2x2-5x + 7 = - 2 (x2 + 52X) + 7 = - 2 (x + 54) 2 + 818, ∵ a = - 2 ＜ 0, ∵ the opening of the parabola is downward, the axis of symmetry is a straight line x = - 54, and the vertex coordinate is (- 54818)

The sum of a prime number and a composite number is 17, and the product is 52. What are the two numbers?

52=2×26=4×13
4 + 13 = 17, so these two numbers are 4, 13

Calculation: (X & # 178; - 2XY + Y & # 178;) - 2 (X & # 178; + 2XY + Y & # 178;)

(x²-2xy+y²)-2(x²+2xy+y²)
=-x²-6xy-y²

40【500-10（x-50）≤8000
eleven

（x-40）{500-10（x-50)}=8000
(x-40)(500-10x+500)=8000
(x-40)(1000-10x)=8000
x^2-140x+4800=0
(x-60)(x-80)=0
x1=60,x2=80

If the solution X of the system {x-3y = k-2,5x-3y = k is equal to y, what is the value of K?

By subtracting the two equations, we can get x = 1 / 2
Because X and y are equal, y = 1 / 2
So x-3y = - 1
So k = 1

The meeting problem of linear equations of one variable on the first day of junior high school
The first time they wanted to be 90km away from a and return to each other immediately after they reached each other. The second time they met at 30km away from B
Ask about the distance between AB and Beijing

Reasoning method:
The first time they met, Jia traveled 90 kilometers. At this time, they traveled a whole journey
When they met for the second time, they made a total of three journeys. A should have made 90 * 3 = 270 km
At this time, a has already made a full journey plus 30 kilometers,
So,
The distance between a and B is 270-30 = 240 km
Equation method
Let AB be x km away
90：（X-90）=（X+30）：（2X-30）
（X-90）（X+30）=90（2X-30）
X^2-60X-2700=180X-2700
X^2-240X=0
X(X-240)=0
X = 0 (rounding off) or x = 240
Therefore, the distance between AB and ab is 240 km

What does the coefficient of a determinant mean?

Determinant is actually the equation of all n * n elements
What you mean is that the elements of a determinant are polynomials that contain only X
Then the expansion according to determinant is the polynomial of X, and the coefficient of a term is the coefficient of X in this polynomial
Another is for a
If we consider the determinant lamda e-A in half, then the coefficient of the determinant is the sum of all the principal subformulas of order N-1 of A
It's not convenient to type matrix. I don't know if you understand