1/2＋5/6＋11/12＋19/20＋29/30＋…… ＋9899/9900

1/2＋5/6＋11/12＋19/20＋29/30＋…… ＋9899/9900

1/2＋5/6＋11/12＋19/20＋29/30＋…… ＋9899/9900 =99-（1/2+1/6+1/12+1/20+1/30+…… +1/9900）=99-（1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+…… +1/99-1/100）=99-（1-1/100）=98.01

1. If the solution of the equation 4x-1 + a = 0 is greater than - 2, then a_____ .
2. When a is a number, the solutions of the equations ax + 4Y = 8, 3x + 2Y = 6 are positive numbers?
It's troublesome to explain the process and thinking clearly,

1. Find the solution x = (1-A) / 4
The solution of the equation is greater than - 2, i.e. (1-A) / 4 > - 2
The solution is A0 y = (12-3a) / (a + 6) > 0
Then solve the system of inequalities and get - 6

The coordinates of the intersection of the line y = 3x-12 and the X axis are________ And the coordinates of the intersection point with the y-axis are_______ The area of the triangle formed by the two intersection points and the coordinate origin is__ .

The coordinates of the intersection of the line y = 3x-12 and the X axis are_ (4,0), and the coordinate of the intersection point with the Y axis is (0-12), and the area of the triangle formed by the two intersections and the origin of the coordinate is 24

A symmetry axis equation of the graph of the function y = cos (2x + π 2) is ()
A. x=-π2B. x=-π4C. x=π8D. x=π

The equation of symmetry axis of this function is 2x + π 2 & nbsp; = k π (K ∈ z). When k = 0, x = & nbsp; − π 4

Idioms are divided into three parts: teaching, flowing, hair, hair, horn, head and tail
What do you want to fill in?

Four five
39
crane
very rare
cop-out

The construction team uses 2 parts of cement, 3 parts of sand and 5 parts of stone to make a kind of concrete
The construction team uses 2 parts of cement, 3 parts of sand and 5 parts of stone to make a kind of concrete. If there are 20 tons of these three materials, how many tons of sand and stone need to be added when all the cement is used up?

20 divided by 2 / 10 = 100 tons. 100x3 / 10 = 30 tons, 100x5 / 10 = 50 tons. Then 30-20 = 10 tons of sand and 50-20 = 30 tons of gravel are needed

The square of known inequality ax + BX + 6

The square of inequality ax + BX + 6

Library English: ()

library.

1. On the number axis, the point whose distance to the origin is 5 represents the number; the point whose absolute value is greater than 0 represents the number; the point whose distance to - 3 is 2 represents the number;
2. On the number axis, the number represented by point a is - 6, and the number represented by point B is + 8, then the number represented by the midpoint C of AB is; after moving AB 3 units to the left, the number represented by point C is; after moving AB 3 units to the left, the number represented by point AB is just opposite to each other
3. As shown in the figure, the number represented by point a is 5, the number represented by point B is 1, then the distance between a and B is; if the number represented by point m is, - 13, and the number represented by point n is 7, then the distance between M and N is

1. On the number axis, the number represented by the point whose distance to the origin is 5 is 5 and - 5; the number whose absolute value is greater than 0 is all positive numbers and all negative numbers; the number represented by the point whose distance to - 3 is 2 is - 1 or - 5; 2. On the number axis, the number represented by point a is - 6, the number represented by point B is + 8, then the number represented by the midpoint C of AB is 1; move AB to the left

The function f (x) = the square of X is a decreasing function on - 2mx + 3 and an increasing function on [- 2. Positive infinity]. Find the value of F (2)

F (x) = (x-m) &# 178; - M & # 178; + 3 axis of symmetry x = m
The function f (x) = the square of X - 2mx + 3 [- ∞, - 2] is a decreasing function, and the function f (x) = the square of X is an increasing function on [- 2. Positive infinity]. We can see that the axis of symmetry x = - 2
∴m=-2
f(x)=x²+4x+3
f(2)=2²+4*2+3=15