Regarding the study of the first year of high school, please help

It's a nascent syndrome, and it will be fine after a while, but you have to take advantage of it and try to keep it as short as possible.

Physical chemistry is indeed more difficult to learn in the first year of high school, so be serious, calm down and read slowly. Don't worry.

I'm the same way, it's just that I didn't adapt to it in the early stage, when I first entered high school, I scored 97 points in the class and ranked third, and then I could only take 60 in a month, I was due to family and school reasons, and I hope that the landlord and the family have a good relationship, talk more, confide in my heart, I sometimes ask the teacher, and I have a good relationship with the teacher, I often ask them if it's too early, this helps and makes me like the teacher, and it can also improve concentration, so now I'm very good at it, but to be honest, high school and junior high school are completely incomparable, because I rely on mixing in the first and second years of junior high school 3 years of hard work is the point It's not that I'm smart It's just that it's really difficult In short, the mentality is the first I hope the landlord will get better soon, just like me back then.

Take your time, don't rush, anyway, I am a very good person, a smart person, when I encounter a problem, I think so, calm down first. Usually eat more chocolate or something, in short, measure yourself first, and that's fine. If you really can't do it, go to the counseling room.

I'm also a freshman in high school now. I also think that there is a lot of content in the daily course, and I think I should practice more questions on a daily basis, which is very helpful.

The last laugh is the victory!

Pick B. I believe that after reading this question, you, like me, will first react to the mean theorem, and the key is how to use it.

If you want the maximum value of mx+ny, you must find an inequality: mx+ny is less than or equal to a certain value. The formulas of the mean theorem are all in the form of a certain sum greater than or equal to a certain product, so if you want to prove that mx+ny is less than or equal to something, you can't directly regard it as the sum formula of mx and ny, you must use the product of mx and ny respectively, and then add them together.

If you apply the mean theorem to the product of the two groups without doing anything, you will get:

mx+ny is less than or equal to (m2+x 2) 2+(n 2+y 2) 2

(m^2+n^2)+(x^2+y^2)]/2

a+b)/2

The equal sign holds if and only if m=x, n=y. However, if you want m=x, n=y, you must a=b. In the problem condition, a is not necessarily equal to b, so the equal sign may not be true, that is, (mx+ny) may not be able to get (a+b) 2, it may always be smaller than (a+b) 2, and (a+b) 2 is not necessarily the maximum value of (mx+ny).

In order to change this situation, it is necessary to make the ratio of the coefficients of m 2 to x 2 and the ratio of the coefficients of n 2 to y 2 a b in the equation obtained by applying the mean theorem; In order to eliminate m2+n2 and x2+y2, the coefficients of m2 and n2 must be the same, and the coefficients of x2 and y2 must be the same. To this end, before applying the mean theorem, mx+ny is rewritten as one ab fraction under the root sign multiplied by ab multiplied by (mx+ny) under the root number

The process is as follows: mx+ny=1 (ab under root)*ab*(mx+ny).

1 (ab under root)*[b*m under root)*(a*x under root)+(b*n)*(a*y)]

Less than or equal to 1 (ab under the root number)*[bm 2+ax 2 2)+(bn 2+ay 2) 2].

1 (ab under root number) * (bm 2 + bn 2 + ax 2 + ay 2) 2

1 (ab under root number) *ab

The equal sign is true if and only if b*m under the root sign = a*x under the root sign and b*n = a*y under the root number.

In this way, because (m 2+n 2) (x 2+y 2)=a b, the equal condition must be satisfied, and the result obtained must be the maximum value of (mx+ny).

Add the two formulas to get m + n + x + y = a+

b because m +x 2mx, n +y 2ny, so 2mx+2ny m +n +x +y i.e. 2(mx+ny) a+b

So mx+ny 1 2(a+b).

Then the maximum value of MX +ny is 1 2 (A+B), I wish you happy studying.

The projection of vector a in the b direction is |a|cosθ。Because a*b=|a||b|cos, so |a|cosθ=[a*b]/|b|=1。

1) Because f(1)=3

So a+1+(1 b)=3

Because f(2)=9 2

So 4(a+1)=2(1 b)=9 2

So a=-4 7

b=4/15

So f(x) = (-3 4)x + (15 4)x2) because f(x) = (-3 4)x + (15 4)x, so the opening of the f(x) image is downward.

The axis of symmetry is x=5 2

So f(x) increases on (- 5 2) and decreases on (5 2, +).

So f(x) increases on [1,5 2) and decreases on (5 2,+).

In fact, systematic learning is to summarize a set of learning routines suitable for yourself according to your own learning methods, so as to increase your learning efficiency, which is definitely needed! But you have to sum up it based on practical experience to suit yourself! So you don't have to blindly copy other people's methods, you can improve and sublimate your methods after reading what others say!

That's the best!

Kiss. In fact, the more things you come into contact with, the more chaotic it becomes. And then lost himself.

What I mean is: do what you think is good. Don't let the outside world affect your best self.

It's good to look at some things, listen to some truths, and refer to some textbooks.

So I recommend you. Or use your own learning methods.

Wasn't it nice before... Why do you have to worry about unnecessary brains?

It depends on the method that suits you. If you can't see someone else, you lose your own. "Handan toddler" is the best proof of this.

You can learn from the experience and methods of others, but you must not use it to completely change your original trajectory, which will only outweigh the losses. Of course, learning requires innovation and exploration, but it must be cyclical. You can slowly change your habits and continue if it's in the right direction; If you're wrong, turn back immediately.

That way it won't make much of a difference. Good luck making your progress soon!