A cylindrical reservoir with a bottom diameter of 40 meters and a depth of 4 meters is filled with water by a pump. It is known that the radius of the water outlet of the pump is 20 cm and the water flow velocity is 1 meter per second. Can the reservoir be filled up in 10 hours?

Cylinder volume
=3.14×（40÷2）²×4
=5024 M3
Pump radius = 0.2m
It takes time to fill up
=5024÷（3.14×0.2²×1）
=40000 seconds
40000 seconds ≈ 11 hours
So: 10 hours is not enough

(x + (x + x ^ 1 / 2)) ^ 1 / 2 is the infinitesimal of order x?
(x + (x + x ^ 1 / 2)) ^ 1 / 2 is the infinitesimal of order x?

Infinitesimal of order 1 / 2 of X

The ratio is 1.1 × 9 / 5 () 3 / 24.6 × 4 / 1 () 2 / 3

（>）（>）

Answers to the winter vacation math homework of grade seven published by Hubei Education Press
Kneel down, as long as the homework 12 to 13 answers, thank you

I only have multiple choice questions. Give them to me
Assignment 12
A D C 6 90 ° 27.5 30 SW 70
Assignment 13
A C D a C 3 flat curve 15 10 AC AB BC 19 28 / 9 65 ° 25'155 ° 25 '
I am also looking for students to copy the back of the title to the process did not copy

The two forces acting on the same point of the object are F1 and F2. When the two forces are in the same direction, the resultant force is a. when the two forces are in the opposite direction, the resultant force is B. when the two forces are vertical, the resultant force is a?

I'll do it. Give me a little time to write the process for you

—55+—54+—53+… +44+45=?
It's - 55 + (- 54) + (- 53) + +44 + 45 + =? It's a big problem. This is the last one after the calculation

-55+(-54)+ -(53)+…… +44+45
=-46+(-47)+(-48)+.+(-55)
= -505

Find the rule: 4, 9, 20, (), (), 185
185, not 195

43,90
law:
9=2*4+1
20=2*9+2
43=2*20+3
90=2*43+4
195=2*90+5

The sum of two prime numbers is 50. What is the maximum product of multiplication of these two numbers?
And how to see it.

The closer the two primes are, the greater the product
50=31+19
The maximum product is 31 × 19 = 589

C language x = 3, the expression (x + +) + (x + +) + (x + +) is equal to how much, the expression (+ + x) + + + x) + + + X is equal to how much, to process

(x + + + (x + + + + (x + +) = 9, there is no problem, the execution is 3 + 3 + 3 = 9, the final x = 6; in different software (+ + x) + + + + + + x) values are different, for example, in turbo C2.0 program execution 4 + 5 + 6 = 15; in Visual C + + 6.0 program execution 5 + 5 + 6 = 16; some also have 6 + 6 + 6 = 18, but the final x is the same

Find rules 1,4,3,8, (), (), 7,16

1、3、5、7、9、……
and
4、8、16、32、……
It's a combination
Then:
【1】、4、【3】、8、【5】、16、【7】、32、【9】、

A cylindrical reservoir with a bottom diameter of 40 meters and a depth of 4 meters is filled with water by a pump. It is known that the radius of the water outlet of the pump is 20 cm and the water flow velocity is 1 meter per second. Can the reservoir be filled up in 10 hours?