F (x) = KX + B (k is not equal to 0), increasing function or decreasing function on R

k> 0 is an increasing function
k

Let f (want) = Xe Λ KX (K ≠ 0)
Find the tangent equation of the curve y = f (x) at the point (0, f (x))

f（x）=xe∧kx(k≠0)
So y / = e ^ (KX) + K (x) ^ 2 * e ^ (KX)
Passing point (0,0)
K=y/=1
So y-0 = 1 * (x-0)
We deduce y = X

Let f (x) be an even function defined on R with a period of 5. If f (3) > 1, f (7) = a2-a-1, then the value range of real number a is ()
A. （-2，1）B. （-∞，-1）∪（2，+∞）C. （-1，2）D. （-∞，-2）∪（1，+∞）

∵ function f (x) is defined on R with 5 as period ∵ f (7) = f (7-5) = f (2) = f (2-5) = f (- 3) and ∵ function f (x) is even function ∵ f (- 3) = f (3) ∪ (7) = f (3) > 1, that is a2-a-1 > 1, that is a2-a-2 > 0, the solution is a > 2, or a < - 1, that is a ∈ (- ∞, - 1) ∪ (2, + ∞)

Ask a few math problems, help it, thank you! List the formula
1. The cylindrical reservoir with a bottom radius of 10 decimeters can store 1570 cubic meters of water. If the depth of excavation is 2.5 meters, how many cubic meters can it store?
2. A 1.2-meter-long cylindrical steel is cut into three sections, and its surface area is increased by 6.28 square decimeters. What is its original volume?
3. A rectangular iron block with a length of 9cm7cm3cm and a square iron block with an edge length of 5cm are fused and cast into a cylinder with a bottom diameter of 20cm. What is the height?
4. How much is the volume of a cubic timber with 6cm edge length processed into the largest cylinder? What is the remaining volume?
5. A cylindrical glass with a volume of 1000 cubic centimeters, the ratio of water height to water height is 1:1, put a cone (the cone is completely in water), the ratio of water height to water height is 3:2, what is the volume of the cone?

1、1570+3.14*0.1*0.1*2.5
2、6.28/4*1.2
3、（9*7*3+5*5*5）/3.14/（20/2)/（20/2)
4、3.14*(6/2)*(6/2)*6
6*6*6-3.14*(6/2)*(6/2)*6
5、1000/5*3-1000/2

There is a thin thread. It takes three fifths of a meter for the first time and seven tenths of a meter for the second time. How many times?

Three fifths is equal to six tenths, and six tenths is less than seven tenths. Therefore, we use more for the second time

Ask a math problem. You need to make a formula
A rectangular glass fiber reinforced plastic container with a floor area of 96 square centimeters and a height of 10 centimeters contains 5 centimeters of water. Now, if you put an iron bead into the water, who will raise it by 2 centimeters. What is the volume of the iron bead? At least a few such iron beads should be put before the water will overflow?

From the meaning of the title, we can know: container volume = bottom area * height = 96 * 10 = 960ml
At present, there is 5cm of water, so the volume of water is 5 * 96 = 480ml
After an iron bead is put in, the water surface rises by 2cm, and the rising volume = the volume of the iron bead = 96 * 2 = 192 cubic cm
Put two iron beads, the water surface rises 4cm, put three, the water surface rises 6cm, but the water surface is 5cm less than overflow
Therefore, it will take at least three quarters for such iron beads to overflow

A bookstore promotes sales by the way of "20 yuan membership card enjoys 20% discount". Under what circumstances do you think it is cost-effective to apply for membership card?
The number of years in which Mr. Lin was born: the sum of 5 is a multiple of 9, the sum of 6 is a multiple of 10, the sum of 7 is a multiple of 11, the sum of 8 is a multiple of 12. Do you know the year in which Mr. Lin was born?

Question 1: spending X Yuan in this bookstore, the equation can be listed as: (1-80%) x = 20 0.2x = 20 x = 100 a: when spending more than 100 yuan in this bookstore, it's cost-effective to get a membership card

In a speech contest for young teachers, there are 10 judges scoring them. One teacher's average score is 9.71. If the highest score is removed, his average score is 9.69. If the lowest score is removed, his average score is 9.82. What are the highest and lowest scores of the teacher?

The highest score is: 9.71 × 10-9.69 × 9 = 9.89
The lowest score was 9.71 × 10-9.82 × 9 = 8.72
So the teacher's highest score is 9.89 and the lowest is 8.72

Math problems, solutions, formulas, thank you
1. How many kilos are 25% less than 20 kilos? 2. The number of male students in a class is 25% of that of female students. 3. The actual output this year is more than 18% of the original plan. The original plan is to complete 2 million yuan this year. How many million yuan is the actual output this year, How many percent more than the original area? (for example) 5. One person deposits 5000 yuan in the bank for two years. If the annual interest rate is 3,75%, it can get several yuan of interest when it matures. 6. Dissolve 15 grams of salt into 100 grams of water. What is the salt content of salt water?

1.20-20x25% 2. The number of students in the class is? 32 million yuan + 2 million yuan x 18% 4. Increased by 10% x 10%, because the square area = side length x side length 5.5000 x 3.75% x 26. Salt content = 15 ÷ (100 + 50) sorry, because there is no calculation answer due to time, but you can use a calculator to calculate, if it is% use a calculator to calculate

1. Party A and Party B work together to make a batch of parts. Party A makes 55% of this batch of parts, 40 more than Party B. how many parts are there in total? 2. Xiao Hong has read 30 pages of a comic book, 40% less than the rest, How many pages is this book in total? This year's rice production has increased by 18% compared with last year. It can be understood as: A. this year's rice production is 82% of last year's; B. last year's rice production is 82% of this year's; C. This year's rice production is 118% of last year's; 4. What is the number 20% less than 45? 2. The number of girls in a class is 50% of that of boys, and what is the number of girls in the whole class?

1. Take the total number of parts as the unit, 1. This batch of parts has a total of 40 △ [55% - (1-55%)] = 400; 2. Take the rest as the unit, 1. This book has a total of 30 △ (1-40%) + 30 = 80 pages; 3. Take last year's rice production as the unit, 1. This year's rice production is 1 + 18% = 118% of last year's, so choose C; 4

F (x) = KX + B (k is not equal to 0), increasing function or decreasing function on R