4-10 / 21 * 3 / 2 + 3 / 7 4 / 5 * 4 / 7 * 5 / 4-1 / 3 1 / 6 + 3 / 4 * 2 / 3 * 1 / 2 How to use simple algorithm for (3 / 4-1 / 3 * 7 / 4) * 3 / 2

4-10 / 21 * 3 / 2 + 3 / 7 4 / 5 * 4 / 7 * 5 / 4-1 / 3 1 / 6 + 3 / 4 * 2 / 3 * 1 / 2 How to use simple algorithm for (3 / 4-1 / 3 * 7 / 4) * 3 / 2

First calculate 1 / 3 × 7 / 4, then equal to 7 / 12
Now the formula is: (3 / 4-7 / 12) × 3 / 2
(3/4-7/12)×3/2
=3/2×3/4-3/2×7/12
Then use the product of 3 / 2 × 3 / 4 - 3 / 2 × 7 / 12!

Find the range of the function f (x) = lgx / X in the interval [1 / 2,1]

It is easy to know that (lgx) ′ = 1 / (x ㏑ 10).. by deriving the function f (x) = (lgx) / x, f '(x) = [(1 / ㏑ 10) - lgx] / X & sup2; ∵ 1 / 2 ≤ x ≤ 1, = = = > LG (1 / 2) ≤ lgx ≤ LG1. = = = > - LG2 ≤ lgx ≤ 0. = = = = > 0 ≤ - lgx ≤ LG2. = = = > 0 ＜ 1 / ㏑ 10 ≤ (1 / ㏑ 10) - lgx ≤ (1 / ㏑ 10) + LG2

If the perimeter of a rectangle is less than 80cm and the area is not less than 100cm, then the value range of X is______ ．

The answer is: 10 ≤ x < 30

How is 5.5.5.1 equal to 24?

1 divided by 5 = 0.25-0.2 = 4.8 4.8 times 5 = 24

If 6sn = an ^ 2 + 3an + 2, A1, A3, a11 are in equal proportion
General term formula for an

As follows:
6Sn=an^2+3an+2
6S(n-1)=[a(n-1)]^2+3a(n-1)+2
6Sn-6S(n-1)=6an=an^2+3an+2-{[a(n-1)]^2+3a(n-1)+2}
an-a(n-1)=3
{an} is an arithmetic sequence, d = 3
A1, A3, a11 are equal ratio sequence
a3^2=a1×a11
A2=A1+d;A4=A1+3d;A9=A1+8d
a3=a1+2d=a1+6
a11=a1+10d=a1+60
(a1+6)^2=a1×(a1+60)
a1=3/4 d=3
Therefore, the general formula is as follows:
an=3/4 +(n-1)×3
an=3n-9/4

Square area 64 square decimeters, how much is perimeter?

8×8=64
Side length = 8 decimeters
Perimeter = 8 × 4 = 32 decimeters

Five numbers, the sum of any three numbers, get 10 different numbers: 15, 16, 18, 19, 21, 22, 23, 26, 27, 29. What is the product of these five numbers?

Let these five numbers be a, B, C, D, e. a + B + C + D + e = 15 +... + 29 / 6 = 36, C + D + e = 29, a + B = 36-29 = 7, C = 15-7 = 8 (the sum of the smallest three numbers must be the sum of ABC). The second smallest number is the sum of a, B, D, so 16-15 is (a + B + D) - (a + B +...)

Let x1, X2 , xn is an integer, - 1 ≤ Xi ≤ 2 (I = 1,2,...) ,n）
At the same time:
（1）x²1+x²2+…… +x²n=2004
（2）x³1+x³2+…… +x³n=2002
Find X &; 1 + X &; 2 + +The maximum and minimum of X &; n

There are s-1, T-1, m-2
Then S + T + 4m = 2004 ①
-s+t+8m=2002 ②
The solution is s = 1 + 2m
t=2003-6m
∵ t>0,∴ m

To pave the floor of a room, 240 square bricks with a side length of 3 decimeters are needed. How many square bricks with a side length of 6 decimeters are needed?

If the side length of 6 decimeters square brick is selected, X pieces, (3 × 3) × 240 = (6 × 6) × x, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 3 × 3 × 2406 × 6, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 60; answer: if the side length of 6 decimeters square brick is selected, 60 pieces are required

What is Kirchhoff's theorem?
What is the content of Kirchhoff's law?

Kirchhoff's law includes the current law and the voltage law. The current law: in the lumped circuit, for any node at any time, the algebraic sum of all branch currents flowing out of the node is equal to zero. The voltage law: in the lumped circuit, at any time, along any circuit, the algebraic sum of all branch voltages is equal to zero