A round wood is 4.6 meters long and 24 cm in diameter. How many cubic meters does it have?

A round wood is 4.6 meters long and 24 cm in diameter. How many cubic meters does it have?

24CM=0.24M
Radius: 0.24m/2 = 0.12M
Vvolume = 0.12 * 0.12 * 3.14 * 4.6 = 0.2079936 (M3)

It takes six hours for a car to transport coal to and from the school. The speed is 30km / h when going and 50km / h when returning. How many thousand kilometers are there between the two places
rice

6 / (1 + 50 / 30) = 3.75 (hours)
3.75 * 30 = 112,5 (km) or
(6-3.75) * 50 = 112.5 (km)

Calculate the intersection of 2009 straight lines, forming () pairs of different opposite vertex angles at most

The number of intersections; (2009-1) * 2009 / 2
There are 2 pairs of vertex angles at each intersection, and the maximum is (2009-1) * 2009 = 4034072 pairs of different vertex angles

Given X / Z / > / X /, then the value of / x + Z / + / y + Z / - / X-Y / is
But I don't understand. Let x = - 1, y = - 3, z = 2
But substituting is negative. Please point out what's wrong

Let x = - 1, y = - 1, y = - 3, z = 2, then / x + Z / + / y + Z / + / y + Z / / / X-Y / = | - 1 + 2 + | - 1-1 - (- 3) = - 1, y = - 1, y = - 1 = - 1, y = - 1, y = - 1, y = - 1, y = - 3, y = - 1, y = - 1, y = - 1, y = - 1, y = - 1, y = - 1 = - 1, y = - 1 = - 1, y = - 1 = - 1, y = - 1, y = - 1 = - 1, y = - 1 = - 1 = - 1, y = - 1 = - 1, y = - 1 = - 1, y = - 1 = - 1, y = - 1, y = - 1 = - 1 = - 1, y = - 1, y = - 1, y = - 1 = - 1, y = - 1 = - | = x + Z - (y + Z) - (X-Y) = 0

Under standard atmospheric pressure, 0 ℃ water endothermic temperature (); energy (); 100 ℃ water endothermic temperature (); energy ();
If water at 10 ℃ is exothermic, temperature () and energy ()
(select "increase", "decrease", "increase", "decrease", "unchanged")

(increase) (increase) (unchanged) (decrease) (decrease)
Well, please pay attention upstairs, because the heat absorbed by 100 ℃ water will vaporize part of the water, so the quality of the water will be reduced accordingly, and the remaining water is still 100 ℃. The quality of the water at 100 ℃ will be reduced, so the energy content will be reduced, of course. I see? (I just went upstairs, but now I'm downstairs due to the modification of the answer.)

The connection between Newton Leibniz formula and differential mean value theorem is urgent!

I think there are two possibilities: 1. The connection between Newton Leibniz formula and the special case of the first mean value theorem of integrals. First of all, let me answer this question. Newton Leibniz formula is actually the general form of the special case of the first mean value theorem of integrals

Does the signed function SGN (x) have an original function?
What is the property of discontinuity of derivative function?

The original function of F (x) = SGN (x) is close
F(x)=|x|,
If f (x) = | x |, then
F'(x)=
1,x>0,
-1,x0,
-1,x

One fourth of 36 is equivalent to 27?

36 × 1 / 4 = 9,9 △ 27 = 1 / 3, equivalent to 1 / 3 of 27

In the arithmetic sequence {an} with odd items, the sum of odd items is 80, and the sum of even items is 75. Find the middle item and the number of items in this sequence

Let the middle term of the sequence be x and the number of terms be n
x·(n-1)/2=75,
x·(n+1)/2=80.
The solution is: x = 5, n = 31

What is 1 + 2 + 3 + 2 + 3 + 4 + 3 + 4 + 5. + 48 + 49 + 50?
This is a mathematical problem. I hope the person who worked it out will give it to me together with the steps

1 + 2 + 3 + 2 + 3 + 4 + 3 + 4 + 5. + 48 + 49 + 50 = (1 + 2 + 3) + (2 + 3 + 4) + (3 + 4 + 5). + (48 + 49 + 50) has 48 brackets
=6 + 9 + 12 +. + 147 because the difference between the two numbers is equal, it is 3
So the original formula = (6 + 147) / 2 * 48 = 3672
The answer is 3672