Math questions, why can t I get the answer right when I do this, it feels very reasonable20

The definition of the odd function is f(x)=-f(-x), so your corresponding odd function there should be -(x 2-2x) which is where it needs to be corrected.

And there is a problem with the logic behind your problem, if you follow your algorithm, then the equation for f(x+2) is -(x 2-2x).

I suggest that you push forward and calculate the [2,4] interval first.

That is, in the interval [0,2], 3f(x)=f(x+2) then 3(x 2-2x)=3x 2-6x=f(x+2), and then let y=x+2, note that the definition domain of y is [2,4], that is, x=y-2. Substituting the original form, then the original form can be written as 3(y-2) 2-6(y-2), which is the formula you require, where the definition domain is the definition domain of y, that is, [2,4].

If you calculate the [-4, -2] interval again, you can add a negative sign to the formula.

This question is incorrect. f(x)=(1/3)f(x+2),∴f(-1)=(1/3)f(-1+2)=(1/3)f(1)=-1/3

f(x) is an odd function, so f(-1)=-f(1)=1, therefore, this question is wrong.

If f(x)=(1 3)f(x+2) is satisfied on (- 0) or [0, ), then it can be solved.

The circled place is correct, and the reason why your answer is wrong may be because the question is wrong and the conditions are missing. Your step is to take (-0) satisfies f(x)=(1 3)f(x+2) and answer takes [0, ) satisfies f(x)=(1 3)f(x+2).

If f(x)=(1 3)f(x+2) is satisfied on [0, ), then the result is.

f(x)=-3x²-18x-24

The odd function satisfies f(-x)=-f(x).

So the red line should be f(x)=-f(x).

f(x) = -x square + 2x

I can't do math problems, but I can understand them as long as I read the answers, and I will have this experience in my life. For any student, when faced with writing a math problem, because there is no idea to solve the problem, they can't do the math problem at all, but they can think about it after looking at the answer. But in fact, as a student, when doing math problems, you must first develop the ability to think for yourself, and never always think about looking at the answers.

Once you get into the habit of reading the answers, you will always want to look at the answers when it comes time to take the exam. <>

When writing homework at home, you will want to help your child complete the homework as soon as possible by reading the answers. However, when children complete their homework, they are generally in a perfunctory state, because when children write math homework, they simply do not think in time. The child does not think, but only knows to copy all the answers in the homework book, and when the teacher asks the child how to solve the problem, the child does not know how to answer the problem at all.

As a parent, when tutoring your child with homework, don't develop the habit of showing your child the answers. <>

In fact, in life, I want to see the answer every time I do a math problem, and only after reading the answer can I really understand the idea of solving the problem. But this is also because of the lack of early examination of some phenomena, as a child every time he looks at the exam questions, he should first review the questions many times. Think about it for yourself in advance, whether such a question will be, and if it really won't, it is better to wait for the teacher to explain it than to always look at the answer.

In fact, for students in the process of learning, if they look at the answers for a long time, it is not good for their thinking ability. Because I have developed the habit of looking at the answers, I will want to peek at the answers when I encounter a question that I don't know, and at the time of every exam, I will gradually develop a problem that I don't like to think. As long as you encounter something you don't know, you will form a habit of relying on answers or relying directly on your mobile phone to search for questions.

I'm the same way, because sometimes when I see this problem, but he can't think of the solution idea for a while, then he can't do the problem, but once he understands the solution idea, the problem is very simple.

Of course, this is also the case. First of all, because you may not think of that point when you think about it, and that point is precisely the key to solving the problem, so when you see the answer, you will suddenly understand.

Yes, I'm like this too, I think it's mainly because I don't have an idea to solve the problem, and after reading the answer, I have a general idea.

Yes, because just looking at the answer loses the desire to do math problems. Math is like that, not knowing the answer can entice people to do it. Life is the same, the future is unknown, so we have to face it with a positive attitude, the unknown can stimulate our interest in exploration, so at least it will not be in vain.

If you can predict the future, then what is the meaning of life!

Strictly cultivating children's good habits of solving math problems is a manifestation of children's academic responsibility. This is the same as building the foundation of a tall building, the better the habit is cultivated, the more solid and stable the foundation will be, and the easier it will be to improve the efficiency of math learning and get good grades. Although it may be difficult to develop good habits at first, if parents or teachers can give positive guidance and motivation to motivate children to be self-motivated about their grades, it is easy for children to accept the formation of good habits.

I think it's right, I still have the ability to think independently when doing math problems, and I can solve them as soon as I see them, so that I can draw inferences from the method in one fell swoop.

I think it's certainly true that you can't easily read the answers when doing math problems, because if you look at the answers while doing math problems, it may affect your thinking and not help you think about the problem correctly.

I think so. After reading the answers, I think you are right, you should do it yourself before you read the answers, and then read the answers after you have done it.

: This question uses a comparative method to analyze the known conditions as follows.

All the money: you can buy 8 kg of pears and 6 kg of apples, or buy 4 kg of pears and 9 kg of apples compared with the second way of buying, the second way of buying is less than the first way to buy 4 kg of pears and equal to 3 kg of apples, that is, the price of 4 kg of pears is equal to the price of 3 kg of apples, using this relationship, you can find out the number of kilograms to buy pears or only buy apples.

You did the right thing.

Solution: Set x yuan per kilogram of pears and y yuan per kilogram of apples.

8x+6y=4x+9y

4x=3y, the total amount of money is $16x or $12y.

Buy only pears: 16x x = 16 (kg).

Buy only apples: 12y y = 12 (kg).

It should be right, and I'm the answer. Process: Set pears x kg, apple y kg z = 8x + 6y

1）z=4x+9y

2) Multiply 2 by 2 to 8x+6y=8x+18y, and the shift term shows that y is 3 and x is 4

The total amount of money is 48 yuan... Hope you are satisfied with the answer.

First of all, it is possible that you are too nervous to relax completely during the exam, and once you are nervous, even the most simple questions will make mistakes, so you should adjust your mentality and treat the exam as a regular practice question.

Then, the word "sloppy" is actually just an excuse, and occasionally getting one or two simple questions wrong can be said to be sloppy, but if you get it wrong often, it's not a matter of habit. One of the ways you think when you're working on a question may be something inappropriate, causing you to make mistakes a lot that you don't realize.

I suggest that you can transcribe all the questions that you thought you could do right but wrong, and then try to do it again, for now you need more to summarize, a complete summary of mathematical knowledge and logical thinking.

If you really want to improve your math scores, you should insist on taking notes, thinking for yourself, and summarizing methods for yourself. You don't need to do a lot of questions, you just need to do each question with your heart, which will be a big change for you.

It's not a matter of sloppiness, it's a matter of mentality and habits of doing questions peacefully. Sloppiness is just an excuse. Do you pay attention to mathematics, when you usually write homework, do you treat the steps very carefully, it is really not good, you just do each problem to draw the important conditions in the problem.

The basis of the paragraph discussion is illogical.

Compare the subtraction of the two formulas to see if the knot is equal to 0 or to 0

In this question, A 2-3-(4A-15)=A 2-4A+12, with A 2-3-(4A-15)=A 2-4A+12=(A-2) 2+8, A belongs to any value of r, (A-2) 2+8>=8>0, so A 2-3-(4A-15)=A 2-4A+12>0, i.e., A 2-3>4A-15