The Enlightenment of mantis on the composition of the second volume of the fifth grade of Chinese s Edition Teach me, I'll give you 20 points!

The Enlightenment of mantis on the composition of the second volume of the fifth grade of Chinese s Edition Teach me, I'll give you 20 points!

The king of Wu wanted to cut down Jing, and told him: "those who dare to admonish die!" at this time, there was a young man under him who knew that admonishment would be useless, but he was killed. But he swam in the backyard with a slingshot, and showed his clothes. Third, the king of Wu asked, "there are

PEP, unit 1 to 8 composition topic

Unit 1: in the East, West, North and south of the motherland, there are many people of our age. How good it is for us to establish contact with each other and make friends. In the name of group or individual, write to the distant primary school students. First introduce our own situation, then talk about the idea of "hand in hand" activities, and put forward feasible suggestions

English conjunctions in sentences unit 1 volume B
tall,you,is,than,brother,your,younger,and

Your brother is tall and younger than you.

Solve the equation 3x (x-3) = 21-2x (5-2 / 3x) in 5 minutes

X=21 -9X=21-10X,X=21

If the generatrix length of the cone is 5cm and the half face is 3cm, then the surface area of the cone is

S bottom = π R ^ 2 = π * 3 ^ 2 = 9 π
S side area = 2 π R / 2 π L * π L ^ 2 = π RL = π * 5 * 3 = 15 π
So the surface area of S cone = s bottom surface + s side area = 9 π + 15 π = 24 π cm ^ 2

1/1*3+1/3*5+1/5*7+1/7*9+.+1/49*51

1/1*3=1/2(1-1/3) 1/3*5=1/2(1/3-1/5)
1/7*9=1/2(1/5-1/7)
1/1*3+1/3*5+1/5*7+1/7*9+.+1/49*51
=1/2(1-1/3+1/3-1/5+.-1/51)
=1/2(1-1/51)
=25/51

Circle C passes through three different points P (k, 0), q (2,0) and R (0,1). It is known that the tangent slope of circle C at point P is 11. Try to find the equation of circle C

The center O is on the vertical bisector of PQ, let (x, y), x = (K + 2) / 2, the center O is also on OP, and it is perpendicular to the tangent on P, that is, its slope is - 1 / 11, so the op line is: y = - 1 / 11 * (x-k), the intersection of the two is: - 1 / 11 * (x-k) = (K + 2) / 2, we get: x = - 11-4.5k, so y = 1 + 0.5K, because OQ = or = R, substitute it into the center coordinates

Given that M is an integer and the point (12-4m, 19-3m) is in the second quadrant, then the value of m ^ 2 + 2005 is

It is known that M is an integer and the points (12-4m, 19-3m) are in the second quadrant,
Then 12-4m < 0
19-3m＞0
The solution is 3 < m < 19 / 3
∵ m is an integer
‖ M = 4 or 5 or 6
When m = 4,
m^2+2005＝4²+2005＝2021
When m = 5,
m^2+2005＝5²+2005＝2030
When m = 6,
m^2+2005＝6²+2005＝2041

If the real number x y satisfies x2 + y2 = 2x, find the value of x2-y2
I think the answer is this:
x2>=0,y2>=0
2x>=0
x2+y2=2x
y2=2x-x2
x2-y2=x2-2x+x2
=2x2-2x
And then calculate it according to quadratic function

X ^ 2 + y ^ 2 = 2x so - y ^ 2 = x ^ 2-2x
So x ^ 2-y ^ 2 = x ^ 2 + (x ^ 2-2x) = 2x ^ 2-2x
=2（x^2-x+1/4)-1/2
=2(x-1/2)^2-1/2
Because x ^ 2 + y ^ 2 = 2x, x ^ 2-2x = y ^ 2
Because y ^ 2 ≥ 0, x ^ 2-2x ≤ 0
So 0 ≤ x ≤ 2
Note H = 2 (x-1 / 2) ^ 2-1 / 2
Because 0 ≤ x ≤ 2,
So when x = 1 / 2, h has the minimum value, - 1 / 2
So when x = 2, H gets the maximum, 4
So the range of H is - 1 / 2 ≤ h ≤ 4

15.5 divided by the quotient of 31 / 5 multiplied by the reciprocal of 0.25, what is the product

15.5/(31/5)x(1/0.25)
=2.5x4
=10