1. The function f (x) defined on R is an odd function, and f (x) = f (2-x). If f (x) is a subtractive function in the interval (1,2), then the function f (x) is a subtractive function in the interval (- 2, - 1)____ Function, in the interval (3,4) is___ Function? (add or subtract) 2. The monotonic decreasing interval of function y = |x ^ 2 + X | is __ I want to know if the numbers - 1 and - 0.5 can be obtained? The answer is yes, but I didn't get it. But I don't think so 3. Given that the value range of function f (x) = 0.75x ^ 2-3x + 4 on interval [a, b] is [a, b], find the values of real numbers a and B

1. The function f (x) defined on R is an odd function, and f (x) = f (2-x). If f (x) is a subtractive function in the interval (1,2), then the function f (x) is a subtractive function in the interval (- 2, - 1)____ Function, in the interval (3,4) is___ Function? (add or subtract) 2. The monotonic decreasing interval of function y = |x ^ 2 + X | is __ I want to know if the numbers - 1 and - 0.5 can be obtained? The answer is yes, but I didn't get it. But I don't think so 3. Given that the value range of function f (x) = 0.75x ^ 2-3x + 4 on interval [a, b] is [a, b], find the values of real numbers a and B

1. Where (1,2) is a subtractive function, so f (1) > F (2), and because f (x) = f (2-x), f (2) = f (0), so f (1) > F (0); f(－2)＝f(4),f(－1)＝f(3),f(4)=f(-2)=-f(2),
F (3) = f (- 1) = - f (1), and since - f (1) < - f (2), f (3) f (- 1),
So (- 2, - 1) is_ Minus_ Function, where (3,4) is_ Increase_ function
2. Y = | x ^ 2 + X | = y = | (x + 1 / 2) ^ 2-1 / 4 |, draw a graph and you can see that the monotonic decreasing interval is
(- ∞, - 1] ∪ [- 1 / 2,0], the fraud interval should be OK
3. F (x) = 0.75x ^ 2-3x + 4 = 3 (x / 2-1) ^ 2 + 1, it can be seen that the value range is [1, + ∞), so if the definition field [a, b] is a monotonic increasing function, then a > 2, b > 2; or if it is a monotonic decreasing function, then < 1A < 2, < 1b < 2
Monotonic reduction rule: solve the equations 0.75a ^ 2-3a + 4 = B, 0.75b ^ 2-3b + 4 = a (< 1A < 2, < 1b < 2
）No solution available
Monotonic increase: solve the equation 0.75x ^ 2-3x + 4 = x, (x > 2) and get x = 4
To take the function value as 1, then x = 2, within [1,4], and f (1)

Function is the corresponding relationship from definition field to value field If you know the definition field and value field, you can determine a function. If you know the value field and definition field, you can know the corresponding law

No. I know that several definition fields and value fields only represent the corresponding law of the function in this interval
It does not represent the correct and complete correspondence rule of the function

Definition field and value field Find y = x ²- Definition field and value field of 6x + 7

The definition domain is x ∈ R,
y=（x-3） ²- 2≥-2,
The value range is y ≥ - 2

How to understand the limit property of sequence function Let f (x) be a basic elementary function, an, a belong to D (f), n = 1,2,..., if the limit of an is a, then f (an) = f (a)

The basic elementary functions are continuous in the definition domain, so there is Lima > F (x) = f (a)

The limit of high number sequence and the limit of function Just a freshman. I don't understand. Ask for guidance (1) Let LIM (n →∞) xn = A and prove that LIM (n →∞) (1 / N) (x1 + x2 +... + xn) = a (2)lim(x→0)x sin(1/x)=0 (3) LIM (x → 8) (1 + x) = 3 under the root sign The first question is proved by the definition of sequence limit, and 23 is proved by the definition of function limit.

Because LIM (n →∞) xn = a
So for any ε> 0, when N1 > 0 makes n > N1 | xn-a | N1
|(1/n)(x1+x2+…+xn)-A|
=|(1/n)[(x1-A)+(x2-A)+...+(xn-A)]|

Higher mathematics sequence limit In the definition of sequence limit, it is said that the existence of n makes it true when n > n. why n > n

n> N means that all items an of the sequence after item n meet:
|An-a|n, if n is large enough (> n（ ε)) After that, the gap between an and a can be arbitrarily small（