Masters help solve math puzzles do what you can .

Represents power. 1:1/（n^2-4）=1/(n^2-2^2)=1/((n+2)(n-2))=1/4(1/n-2-1/n+2)

So the original proposition = 12*(1 1-1 5+1 2-1 6+1 3-1 7......1/98-1/102)

There are the same items that can be rounded up, and those that are too small can also be rounded, so the answer is 12*(1+1 2+1 3+1 4)=25

2: The ability is limited, and it can't be calculated, if a b>=.9 can give you the answer a=27, b=30, and the answer is 171

3;Your ability is limited, so please ask someone else.

4: (n+2) 2-(n+1) 2=2n+3 ......... x1 and x2 firstAll points are divided into a little, and there are 18 points left to be distributed, so the maximum is allocated to a minimum of 18 points 2 and 22 1s, so a+b=19 2+39+2 2*18+22=494

5:c=2+(p-1)*

6: The addition of the two formulas gives b + c = 1554 by a< b gets a maximum of 443, so a+b+c = 1997< p>

a=48 (1 (3 squared - 4) + 1 (4 squared - 4) + ....1 (100 squared - 4)).

56≤a+b≤59，a=29b=30

k=12

It's shorthanded. 1 The split term is select D

2 Discuss with dividing B A is 28 B is 31 Option B

3 12？！I got the question right.

5 p*（p+7）/4

If A's walking speed is 13x, then B's walking speed is 11x.

When you draw a simple picture, it's even clearer.

Solution: The distance between ab=

Then there's a simple follow-up question.

60x (13x-11x) = 30 (hours).

A: It takes 30 hours for A to catch up with B.

Special value methods are available. Let the speed of A be 13m h and the speed of B be 11m h, then ab=24*; When walking in the same direction, A must B catch up when he walks 60 meters more, and 2 meters more per hour, so it takes 30 hours.

If you don't think it's rigorous, change 13 to 13x and you're strict, hehe.

It's a matter of pursuit.

Solution: If A's walking speed is 13x, then B's walking speed is 11x.

distance between ab=

60x (13x-11x) = 30 (hours).

A: It takes 30 hours for A to catch up with B.

Let it take X hours for A to catch up with B, and the speed of A and B is 13a and 11a respectively

13a * x =11a*x+(13a+11a)*

x=30

Solution: To spray this herbicide in a 10-hectare corn field, you need x milliliters of herbicide.

Corn: (ml: ha) 60:1

60:1=x:10

x=60*10

x = 600 If you have 100 ml of such herbicide, you can spray x hectares of rice fields.

Rice: (ml: ha) 55:1

55:1=100:x

x=20/11

f[g(x)]=2(kx+b)+3,g[f(x)]=k(2x+3)+b

f[g(x)]=g[f(x)] is true for the x constant of any Laiyi, then the source 2(kx+b)+3=k(2x+3)+b, i.e., b=3k-3

g(x)=kx+b=g(x)=kx+3k-3g(1)=k+3k-3=4k-3

g(-1)=-k+3k-3=2k-3

When k>0, g(x) is monotonically bained increments on x [-1,1], with a maximum of dug(

zhi1), the minimum value is g(-1).

So daog(1)-g(-1)=2k=2, get k=1When k<0, g(x) decreases monotonically on x [-1,1], with the maximum value being g(-1) and the minimum value being g(1).

So g(-1)-g(1)=-2k=2, we get k=-1 so when k=1, b=0, and when k=-1, b=-6

The formula for calculating the circumference of a circle.

1., known diameter: c= d

2. Known radius: c=2 r

3. Known perimeter: d=c

4. Half of the circumference of the circle: 1 2 circumference (curve).

5. The circumference of the semicircle: 1 2 perimeter + diameter (2 + 1) area calculation formula:

1. Known radius: s= r 2;

2. Known diameter: s= (d 2) 2;;

3. Known perimeter: s= [c (2 )]2;;

The side area of the cone = 1 2 The length of the bus bar The circumference of the bottom surface of the cone = the radius of the bottom surface of the cone The length of the busbar.

Surface area of the cone = base area + side area s = r 2 + ra (Note a = busbar) volume of the cone = 1 3sh or 1 3 r 2h height of the cone = (bus 2 - radius of the bottom surface of the cone 2) re-squared;

The cone has no circumference and he is a three-dimensional figure.

Hope that helps you :)

Area of a circle: s = r , d 2) Circumference: d,2 r

The area of the cone: 2 r*high, 2 d

Plant three trees at both ends and midpoint of the tape measure first to ensure that the three trees are in a straight line.

Go through the line at one end and midpoint of the first three trees to determine where the fourth tree will be planted.

The principle of the design is to determine a straight line at two points.