Given that the zero point of function f (x) = 2x-b is x0, and x0 ∈ (- 1,1), then the value range of B is () A. （-2，2）B. （-1，1）C. （−12，12）D. （-1，0）

From the meaning of the question, we can get 2x0-b = 0, so there is & nbsp; x0 = B2, and then we can get - 2 < B < 2 from - 1 < B2 < 1, so we choose a

If f (x) is an odd function whose domain is r, and f (x) has a zero on (0, positive infinity), then f (x) has several zeros

Let f (x) = x + 1 / X-2, the x-th power of the inequality f (2) - k * 2 ≥ 0 hold on X ∈ [- 1,1], and find the range of K
It's better to write in detail, to be able to understand,

2^2+1/(2^x)-2-k*x^2>=0
k=0
So the minimum value on the right is 0
When t = 1, i.e. x = 0, the equal sign holds
So the minimum value on the right is 0

An analysis of the mistakes in Mathematics in grade one of junior high school

Pass on the title to help you analyze

Test paper analysis (grade one mathematics) 100 points
120 actual: 120
Mainly write the score
If it's good, give it five points

Do the problem carefully, listen carefully in class, the teacher's education is good, usually do more exercises, practice more, remember the knowledge points firmly, you can't find much more if you start to talk about it, mainly flattering the teacher, boasting about the teacher's wise education ~

There are two ships a and B in a long straight river. Now there are two ships a and B going downstream at the same time. When ship B arrives at place B, it is informed that it needs to return to place C immediately to carry out the task. Ship a continues to sail downstream. It is known that the speed of both ships a and B in still water is 7.5 km / h, the speed of water is 2.5 km / h, and the distance between a and C is 10 km It took four hours to reach C. how far is ship a from B when ship B arrived at C from B?

(1) The counter current speed of C between a and B is: 7.5-2.5 = 5 (km / h), and the forward current speed is: 7.5 + 2.5 = 10 (km / h). Suppose the distance of BC is x km, the meaning of the question is: (10 + x) △ 10 + X △ 5 = 4, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 10 + X10 + X5 = 4, & nbsp; & nbsp

70 questions on addition, subtraction, multiplication and division of rational numbers
It's a calculation problem, not a text problem, not even an application problem! (each problem should have addition, subtraction, multiplication and division operation)
It's a calculation problem, not a text problem, not an application problem, not even a geometry problem

It's really troublesome! (1) calculation: (1) 23 + (- 73) (2) (- 84) + (- 49) (3) 7 + (- 2.04) (4) 4.23 + (- 7.57) (5) (- 7 / 3) + (- 7 / 6) (6) 9 / 4 + (- 3 / 2) (7) 3.75 + (2.25) + 5 / 4 (8) - 3.75 + (+ 5 / 4) + (- 1.5) (2) simple calculation: (1) (- 17 / 4) + (- 10 / 3) + (- 13 / 3) + (

In the mixed operation of multiplication and division of rational numbers, the division is first transformed into (), then determined (), and finally the result is obtained

Fraction, simplest fraction

How to calculate the mixed operation of rational numbers is correct, and how to determine the sign of multiplication of rational numbers,

First of all, remember the basic rules, and then do more questions
The sign is to see the number of minus signs. When it is odd, it is in place negative. When it is even, it is in place positive~

Division of rational numbers (1)
5. If the product of two numbers is equal to 1, then one of the numbers is called the (), also called them (), that is, if a is multiplied by B = 1, then a and B (); if a and B are reciprocal, then ()
12. Given that a and B are opposite numbers, and a is not equal to o, what is the value of 3A + 3B + B / A-CD?

5. If the product of two numbers is equal to 1, then one of them is called the reciprocal of the other, which is also called them (reciprocal). That is, if a is multiplied by B = 1, then a and B (a * b = 1); if a and B are reciprocal, then (AB = 1). 12. It is known that a and B are opposite to each other, [C and D are reciprocal], and a is not equal to o, then 3A + 3B + B

Given that the zero point of function f (x) = 2x-b is x0, and x0 ∈ (- 1,1), then the value range of B is () A. （-2，2）B. （-1，1）C. （−12，12）D. （-1，0）