|What does A-B | mean and its geometric meaning? What if a is - 1 and B is 1

|What does A-B | mean and its geometric meaning? What if a is - 1 and B is 1

|A-B | denotes the absolute value of the difference between a and B. the absolute value of a positive number is itself; the absolute value of a negative number is its opposite; for example, a = - 1, B = 1; then | A-B | = | - 1-1 | = | - 2 | = 2;
The geometric meaning is the distance between a and B

And conceptual geometry are the contents of that book?
What's more, is it necessary to study chemistry first? Is it necessary to study mathematics first?

In science
Derivative is optional 2-2, geometry proof is optional 4-1
Chemistry elective 4 is a compulsory part of the college entrance examination. The title of the elective is to choose a book from 2, 3 and 5
Compulsory 3 of mathematics focuses on algorithm, program, statistics and probability, which will be further studied in elective 2-3 of mathematics. It is the basis of 2-3. If you think there are too many examples of probability in compulsory 3, you can choose to learn the permutation and combination in advance. These two books actually test one's ability to mathematics, and really test one's brain! They need a lot of practice, Otherwise it will be very painful!
That's about it!

Geometric meaning of derivative
Such as the title`````````````
What is the geometric meaning of derivative

The derivative of the point is the slope of the point

There are 135 people in total, 50 of them are selected, and their per capita monthly water consumption is 4.3 tons. Then how much is the per capita monthly water consumption of 135 people and the average per capita monthly water consumption

An important function of statistics is to estimate the overall situation with the sample situation
Here, the situation of 135 people is estimated by the situation of 50 people, so they are 4.3 tons and 4.3 tons respectively

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1. If both sides of the triangle ABC are 4cm and 6cm, then the perimeter of the triangle is
2. If 2 ∠ a = 3 ∠ B + 3 ∠ C in △ ABC, then ∠ A is equal to____ Degree
3. If ∠ B - ∠ C = 15 ° and ∠ a = 75 ° in △ ABC, then ∠ B=____ °

1 .2

(square of 2A + square of 3AB + square of B) - (square of a + AB)

(square of 2A + square of 3AB + square of B) - (square of a + AB)
=2a²+3ab+b²-a²-ab
=a²+2ab+b²
=(a+b)²

Let f (x) have the first order continuous derivative on [a, b], and ∫ (a, b) f (x) DX ≤ M / 4 (B-A) ^ 2
The two numbers in ∫ () represent the upper and lower limits respectively

There exists C (I) ∈ (a, b) such that f '(C (I)) = 0 (I = 1,2,3... N) [I is a subscript]
Let a

1. Mix 4% and 12% brine to obtain 80 g and 7% brine. If 20 g of 6% brine is added, 6.8% brine will be obtained. At the beginning, how many grams of each brine?
2. Car a and car B start from a and B at the same time and run in opposite directions. After 50 minutes, the two cars meet at C, and then car B arrives at a in another 40 minutes. After arriving at the destination, the two cars have a rest for 10 minutes and then return, and meet again 24 kilometers away from C. how many kilometers has car a traveled?
3. Xiaohong has walnuts and pistachios, of which 17 walnuts are three times as many as pistachios. She eats 7 walnuts and 2 pistachios every day. After a few days, there are 5 walnuts and 7 pistachios left. How many walnuts and pistachios does Xiaohong have?

1. The concentration of 4% is x, the concentration of 12% is Y: 0.96x + 0.88y = 74.40.04x + 0.12y = 5.6, then x = 40.4, y = 39.6 3. Let walnut be x, pistachio be y, and days be t. (1) x = 3Y + 17 (2) x-7t = 5 (3) y-2t = 7

When x < 32, the maximum value of the function y = x + 82x-3 is___ ．

∵ when x ＜ 32, 3-2x ＞ 0. Let 3-2x = t, then x = 3-t2 ∵ y = x + 82x-3 = 3-t2-8t = 32 - (T2 + 8t) ≤ 32-2 × & nbsp; 2 = - 52. When T2 = 8t, t = 4, the equal sign holds, then ymax = - 52

Finding the derivative of y = Cotx xsinx

y=cotx-xsinx
y'=-(cscx)^2 - sinx -xcosx