Reading extracurricular books often can improve our knowledge and correct the wrong sentences

Reading extracurricular books often can improve our knowledge and correct the wrong sentences

Reading extracurricular books often can improve our knowledge

We can improve our knowledge by reading extra-curricular books

We can increase our knowledge by reading extracurricular books

The perimeter of the rectangle is 240 meters, and the ratio of length to width is 5:3. How many square meters is the area of the rectangle?

5 + 3 = 8240 △ 2 = 120 (m) length: 120 × 58 = 75 (m) width: 120 × 38 = 45 (m) area: 75 × 45 = 3375 (M2). Answer: the area of this rectangle is 3375 m2

What is the octave of a plus the octave of B?

If the equation 2A = | AX-1 | (a ＞ 0 and a ≠ 1) has two real roots, the value range of a is obtained

If the equation 2A = | AX-1 | (a > 0 and a ≠ 1) has two real roots, then the image of function f (x) = | AX-1 |, and the line y = 2A have two intersections. As shown in the figure, the combination of number and shape can get 0 ＜ 2A ＜ 1, and the solution can get 0 ＜ a ＜ 12, so the range of a is (0, 12)

Xinxin's tabletop is a circle with a radius of 5 decimeters. She wants to lay a tablecloth with a diameter 3 decimeters larger than the diameter of the table on the table. What's the area of the tablecloth?

2 times 5 + 3 = 13 (decimeter) 13 divided by 2 = 2 / 2 of 13 (decimeter) 13 / 2 square × 3.14 = 132.665 (square decimeter)

The volume of a cone is 32 cubic decimeters, its bottom area is 8 square decimeters, what's the height of the cone

32 ／ 1 / 3 ／ 8 = 12
Because V-cone = one-third sh, V divided by one-third s = H

Who's going to fill in the problem of operation symbols?
3333=1
6666=22
9999=333
Add appropriate operation symbols to the numbers on the left side of the equal sign to form the formula of 1, 22333. Who will have a try?

1、 3333 = 1, 14:
33/33=1,(3+3-3)/3=1,(3+3)/(3+3)=1,3+3/3-3=1,3-3+3/3=1,(3-3+3)/3=1,3-(3+3)/3=1
3*3/3/3=1,3/3+3-3=1,3/(3+3-3)=1,3/3-3+3=1,3/(3-3+3)=1,3/3*3/3=1,3/3/3*3=1
2、 6666 = 22, no solution
3、 9999 = 333, no solution

Derivation of Higher Mathematics: (LN (sin2x)) '

This is the derivative of a composite function
Let t = 2x
Let u = sin t
Let v = ln U
that
v'x = v'u * u't * t'x
= 1/u * cost * 2
= 1/(sin(2x)) * cos (2x ) * 2

It is known that the density of iron is 7.9x1000kg/m3. There is an iron ball with a mass of 1.59kg and a volume of 300 cubic centimeter

V Fe = m Fe / ρ Fe = 1.58kg / (7.9 × 10 ᦉ 179; kg / m ᦉ 179;) = 2 × 10 ᦉ 710; (- 4) m ᦉ 179; = 200cm ᦉ 179;
V iron < V, so the ball is hollow
V air = V-V iron = 300cm & # 179; - 200cm & # 179; = 100cm & # 179;