Calculation: 1 + 2-3-4 + 5 + 6-7-8 + 9 + 10-11-12 + +2005+2006-2007-2008．

Calculation: 1 + 2-3-4 + 5 + 6-7-8 + 9 + 10-11-12 + +2005+2006-2007-2008．

The original formula = (1 + 2-3-4) + (5 + 6-7-8) + (9 + 10-11-12) + +（2005+2006-2007-2008）=（-4）+（-4）+（-4）+… +（-4）=（-4）×502=-2008．

Calculate 1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 2 + 1 of 666666 * 666666

1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 / 666666 * 6666661 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 can be calculated as 2 1 + 52 2 + 42 3 plus a 6, that is 36, that is 36 / 666666 * 666666, that 36 is simpler, that is 6 * 6, then = 6 * 6 / 666666 * 666666 answer = 1 / 111111 * 11111 hope I

Simple calculation of 1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 of 66666 × 66666

1 ＋ 2 ＋ 3 ＋ 4 ＋ 5 ＋ 6 ＋ 5 ＋ 4 ＋ 3 ＋ 2 ＋ 1
=66666 × 66666 / 6 × 6
=11111 × 1 / 1111
=12345541 / 321

1+2+3+4+5+6+5+4+3+2+1666666×666666．

1+2+3+4+5+6+5+4+3+2+1666666×666666，=(1+5)+(2+4)+(3+3)+6+(5+1)+(4+2)666666×666666，=6×6666666×666666，=1111111×111111，=112345654321．

If the line y = KX + B is parallel to the line y = - 2x and intersects with another line y = x + 3 at a point on the Y axis, then the analytical expression of the line is?

The line y = KX + B is parallel to the line y = - 2x
So, k = - 2
The intersection of y = x + 3 and another line y = x + 3 on the y-axis
So, all distances are the same, all are 3
Therefore, the analytical expression of the straight line is y = - 2x + 3

The sum of the first n terms of the equal ratio sequence {an} is SN. For any n belonging to N + points (n, Sn), they are all in the x power of the function y = B + R 1. Find the value of R
When B = 2, denote BN = n + 1 / 4An to find the first n terms and TN of sequence BN

Sn = B ^ n + R, A1 = S1 = B + R, S2 = a1 + A2 = B ^ 2 + R, A2 = B ^ 2-B, S3 = a1 + A2 + a3 = B ^ 3 + R, A3 = B ^ 3-B ^ 2, equal ratio sequence {an}, A2 ^ 2 = A1 * A3, r = - 12. B = 2, an = 2 ^ (n-1) BN = n + 1 / 4An = n + 1 / 2 ^ (n + 1), equal difference + equal ratio, sum TN = (1 + n) * n /

In vacuum, there are two point charges 20 cm apart, and the amount of charge is 2 times 10 to the power of minus 8 and minus 8 times 10 to the power of minus 8, respectively

r=20cm=0.2m
Electrostatic force F = kq1 * Q2 / R ^ 2 = (9 * 10 ^ 9) * (2 * 10 ^ - 8) * (8 * 10 ^ - 8) * / (0.2 * 0.2)
=3.6*10^-4 N
The electric field intensity direction of two different charges at the midpoint of the line is the same
Combined field strength e = kq1 / [(R / 2) ^ 2] + KQ2 / [(R / 2) ^ 2] = K (Q1 + Q2) / [(R / 2) ^ 2]
=(9*10^9)(2*10^-8 +8*10^-8)/(0.1*0.1)=9*10^4 N/C

The solution set of inequality x2 -- 2 ax + A + 2 "0" of X is m. if [1,4] contains M, what is the value range of real number a,
The solution set of inequality x2 -- 2 ax + A + 2 "0" of X is m. if [1,4] contains M, what is the value range of real number a,

When the original formula is transformed into (x-a) ^ 2-A ^ 2 + A + 22 or A2 or Xa, x-a

Given that a and 2b are reciprocal to each other, - C and 2 / D are opposite to each other, | x | = 4, the value of 4ab-2c + D + 4 / X is obtained

It's just that I'm on the first day of junior high school. But I can do this problem. A and 2b are reciprocal, a × 2B = 1 ∵ - C and 2 / D are opposite, C + 2 / D = 0, 2C + D = 2 (- C + D / 2) = 0 ∵ x | = 4, x = 4 or - 4. The meaning of the problem is: when x = 4, 4ab-2c + D + 4 / x = 2 × 2ab-2c + D + 4 / x = 2 × 1-0 + 4 / 4 = 3, when x = - 4

When k is the value, the definition field of function y = LG (KX ^ 2 + X + 1) is r, and when k is the value, the value field is r? Detailed process, thank you

The definition field is r, which means that G (x) = KX ^ 2 + X + 1 > 0 holds for all x constants
So k > 0, delta = 1-4k1 / 4
The value range is r, which means that the value range of G (x) must contain all numbers > = 0, so it has an intersection with the X axis
K = 0, g = x + 1
K0, must have delta = 1-4k > = 0, that is K