Primary school Chinese Grade 6 Volume 1 unit 7 composition

Primary school Chinese Grade 6 Volume 1 unit 7 composition

When I think of my childhood, I also think it's funny. Childhood is really a wonderful time. I remember when I was six or seven years old, there was a thing that I still remember. It was a dark night. There was a bright moon hanging in the sky, and birds were singing in the orchard from time to time

450 words content: to the homes for the aged, please speak on behalf of the young pioneers

Dear Grandparents: Hello! In this warm spring day, we are very happy to visit you on behalf of the young pioneers of the whole school, and try our best to do what we can for the grandparents, hoping to bring happiness to the grandparents in this short time

Urgent solution of mathematical problems to answer the points to the process
The second power of (2a + 1) - 2 (2a + 1) + 3, where a = radical 2
(a-radical 3) (a + radical 3) - A (a-6) where a = radical 5 + 1 / 2
(3) to the second power of a - AB + 7) - (5ab-4 times the second power of a + 7) where a = 2 and B = 1 / 3

1. (2a+1)^2-2(2a+1)+3=(2a+1-1)^2+2=4a^2+2=102. (a-√3)(a+√3)-a(a-6)=a^2-3-a^2+6a=6a-3=6√5+3-3=6√53. (3a^2-ab+7)-(5ab-4a^2+7)=3a^2-ab+7-5ab+4a^2-7=7a^2-6ab=7*4-6*2/3=28-4=24

Where is the center of a triangle? In other words, how to make the center of a triangle?

Only equilateral triangles have centers
It's the intersection of the three bisectors, or the intersection of the high bisectors, or the intersection of the middle bisectors
They are at the same point
If it's the center of gravity
Is the intersection of the three middle lines of the triangle

It is known that a > 0, b > 0, C > 0, and a + B + C = 1. ABC is less than or equal to 1 / 27, 2.1/a + 1 / B + 1 / C is greater than or equal to 9

(1) A + B + C ≥ 3 * triple root ABC
1 ≥ 3 * triple root ABC
abc≤1/27
（2）（1/a+1/b+1/c）（a+b+c）=1+b/a+c/a+1+a/b+c/b+1+a/c+b/c
=3+（a/b+b/a）+（c/a+a/c）+（c/b+b/c)≥3+3*2=9

What is the relationship between differential, integral, definite integral and calculus? Why?

Calculus is the combination of differential and integral
Differential and integral are inverse operations, just like multiplication and division
Definite integral is the operation of calculus in a certain initial value. There is a constant after indefinite integral, while definite integral is directly equal to a numerical value

A, B, C, D four people stand on the seven steps, if each step stands three people at most, and the people on the same step do not distinguish the location of the station, what are the different kinds of station methods?
Seeking the detailed solution
It's very simple. You're all wrong. The answer is 7 ^ 4-7 = 2394

1.1111 station, A47
2 211 station, c24a37
Station 3 31 c34a27
A47 + C24A37 + C34A27=2268
There are 2268 different standing methods

Given z = u ^ V, u = ln (x ^ 2 + y ^ 2) ^ (1 / 2), v = arctan (Y / x), find DZ

Hello!
This is a problem of total differentiation
first
dz=d(u^v)=vu^(v-1)du+u^vlnvdv （1）
then
du=dln(x^2+y^2)^(1/2)=(xdx+ydy)/(x^2+y^2)^(1/2)
dv=darctan(y/x)=dy/x[1+(y/x)^2]-ydx/x^2[1+(y/x)^2]
Du and DV, as well as u, V into (1) can be obtained DZ, you bring it in, I'm not convenient typing here, thank you

Find the answer of x2 + (56-x) 2 = 100
X²+（56-X）²=100

X²+（56-X）²=100
X²+X²-112X+3136=100
2X²-112X+3036=0
X²-56X²+1518=0
△=56²-4×1518

Dividing by a number is equal to multiplying by the reciprocal of the number. This rule applies to both fractions and integers, right

The rule that "dividing by a number is equal to multiplying by the reciprocal of the number" is correct
For example: a △ B = a × (1 / b)
First, we analyze the formula (a ／ b). Since the operation is defined, we have determined that B ≠ 0, otherwise we have a meaningless problem. Therefore, we do not need to consider whether B has a reciprocal, that is to say, B must have a reciprocal (1 / b)
However, it should be noted that when doing applied problems or geometric problems, you must consider the conditions of the Division letter with letters