The main contents of the first volume of the sixth grade Chinese textbook

The main contents of the first volume of the sixth grade Chinese textbook

Well, what's the content

The content and illustrations of the experimental edition of Chinese textbook are very rich

First, the experimental version of the Chinese textbook is rich in content
Second: the experimental version of the Chinese textbook is rich in content and exquisite in illustrations
That's what our teacher taught

It is known that the sequence {an} satisfies A1 = 1, an + 1 = {1 / 2An + N, n is odd, an-2n, n is even}
(1) Let BN = a2n-2 (n is a positive integer), prove that {BN} is an equal ratio sequence, and find its general formula;
(2) Find the sum s of all even items in the first 100 items of the sequence {an}
Asking for advice, asking for advice

(1) According to the known conditions:
B (n + 1) = A2 (n + 1) - 2 = a [(2n + 1) + 1] - 2 = 1 / 2A (2n + 1) + 2n + 1-2 = 1 / 2A (2n + 1) + 2N-1 = 1 / 2 (a2n-2x2n) + 2N-1 = 1 / 2a2n-2n + 2N-1 = 1 / 2a2n-1 = 1 / 2 (a2n-2) (in this process, we need to treat 2n + 1 and 2n as a whole, which are odd and even numbers respectively)
So B (n + 1) / BN = 1 / 2 = equal ratio, B1 = A2-2 = - 1 / 2, BN = (1 / 2) ^ n-1
(2) According to (1), BN = a2n-2 = (1 / 2) ^ n-1, so A2N = (1 / 2) ^ n + 1
s=a2+a4+a6+…… a100=1/2+1+(1/2)^2+1+(1/2)^3+1+…… +(1/2)^50+1=51-(1/2)^50
I hope there are no calculation errors

Try to determine the number of real roots of the equation x + | lgx | = 2

x+|lgx|=x+lgx(x>=1)
When x-lgx (0lge > 1 / 10), G '(x) > 0, X

How many seconds is an hour?

1 hour = 60 minutes = 60 * 60 seconds = 3600 seconds, just remember 60 carry

1999x square - 2000x + 1 = O

(1999x-1)(x-1)=0
x=1/1999,x=1

When m is the value, the fifth power of polynomial (2-6m) x - the square + 1 of 3mx is the quadratic binomial of X, and write this polynomial

Because it's about the quadratic binomial of X,
Therefore, 2-6m = 0
M = 1 / 3 (1 / 3)
So, the original formula = - x squared + 1

The original price of a TV set is 2400 yuan, but the current price is 1600 yuan. How much is the price reduction?

（2400-1600）/2400=?

The side area of a cylinder is 188.4dm2, and its bottom radius is 2DM. What is its height?

188.4 ÷ (2 × 3.14 × 2) = 188.4 ÷ 12.56 = 15 (decimeter) a: its height is 15 decimeters

How to disassemble the absolute value sign
Do you want to change the number? If the absolute sign is minus, it becomes plus. Right

How to get rid of the absolute value sign?
According to the meaning of absolute value, for ∣ a ∣,
When a ≥ 0, ∣ a ∣ = a; when a < 0, ∣ a ∣ = - A