1949^2-1950^2+1951^2-1952^2+… +2001^2-2002^2

1949^2-1950^2+1951^2-1952^2+… +2001^2-2002^2

1949^2-1950^2+1951^2-1952^2+… +2001^2-2002^2=(1949-1950)(1949+1950)+(1951-1952)(1951+1952)+…… +(2001-2002)(2001+2002)=-3899-3903-…… -4003=-(3899+3903+…… +4003)=-(3899+4003)×27÷2=-106677

Square of 1949 - square of 1950 + square of 1951 - square of 1952 + Square of 1997 - square of 1998 + square of 1999

Use the formula of square of a - square of B = (a + b) * (a-b)

Square of 1949, square of 1950 + square of 1951 - square of 1952. + square of 2011 - square of 2012
1949 square - 1950 square + 1951 square - 1952 square. + 2011 SQUARE - 2012 square

Square of 1949-1950 + square of 1951-1952. + square of 2011-2012 = (1949-1950) (1949 + 1950) + (1951-1952) (1951 + 1952) +... + (2011-2012) (2011 + 2012) = - (1949 + 1950) - (1951 + 1952) - (2011 + 2012) = - (1949 + 1950 +... + 2011

Calculate the square of 1949-1950 + 1951-1952 +... + 1997-1998

Square of 1949-1950 + square of 1951-1952 +... + square of 1997-1998 = (1949 ^ 2-1950 ^ 2) + (1951 ^ 2-1952 ^ 2) +... + (1997 ^ 2-1998 ^ 2) = (1949-1950) (1949 + 1950) + (1951-1952) (1951 + 1952) +... + (1997-1998) (1997 + 1998) = - (1949 + 1950 + 1951 + 1952 +... + 1997 + 1998) = - (1949 + 1998) X50 / 2 = - 98675

What is 1 ÷ (the negative fifth power of 3 × 10) equal to?

1/3×10^5

A telecommunication company provides two kinds of charging standards for mobile communication services. The monthly fee of scheme a is 20 yuan · the call fee is 0.5 yuan. The monthly fee of scheme B is 50 yuan·
It costs 0.3 yuan
(1) If scheme a is used instead, how many minutes can a user talk?
(2) Will the above two schemes have the same call time and the same charge?
(3) If you are a user of this telecommunication company, now please choose one of the solutions. How would you choose

(1) The 200 minute call cost of scheme B is: 50 + 0.3 * 200 = 110. If scheme a is used, the call minutes can be: (110-20) / 0.5 = 180 minutes
(2) Univariate equation
Assuming that the call time is x, the same call cost is 20 + 0.5x = 50 + 0.3x, and the solution is x = 150 minutes, and the call cost is 95 yuan
(3) When the call time is 150 minutes, the charge of the two schemes is the same. Suppose the call time is X
If scheme a is selected, it will be 20 + 0.5x150, so scheme B is more affordable when the call time exceeds 150

As shown in the figure, take any point m on the side BC of the square ABCD, pass through point C to make cn ⊥ DM, and cross AB to N. let the intersection of the diagonal of the square be o. try to determine the relationship between OM and on, and explain the reason

The square is the square of the quadriquadrilateral ABCD, the square is square, DC = BC, DC = BC, and \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ ? Cm The relationship between OM and on is om = on and OM ⊥ on

An object with a mass of 60000mg may be ()
A. A desk B. a rubber c. a brick D. an egg

60000mg = 60g = 0.06kg. A, the weight of a desk is about 20kg, which is not in line with the theme; B, the weight of a rubber is about 10g, which is not in line with the theme; C, the weight of a brick is about 3kg, which is not in line with the theme; D, the weight of 10 eggs is about 1kg, and 1kg = 500g, so the weight of an egg is about 50g, which is 60g

Xiaoming, Xiaoqiang and Xiaohai go out in a taxi together. They agree to share the fare according to the length of their journey. Xiaoming gets off at 1 / 4 of the whole journey and Xiaoqiang gets off at 3 / 5 of the whole journey. Only Xiaohai gets to the destination. Xiaohai takes the fare of 37 yuan. How much does Xiaoming and Xiaoqiang pay for Xiaohai?
Here's the formula, Sheila

According to the meaning of the question, it should be calculated according to the percentage of the total distance of three people. If the road length is 1, the sum of the total distance of three people is: 1 / 4 + 3 / 5 + 1 = 37 / 20
Xiao Hai paid 37 yuan for the fare
On average, it costs 1 yuan for every 1 / 20 of the total distance
After sharing, Xiaoming is 5 / 20, Xiaoqiang is 12 / 20 and Xiaohai is 20 / 20
Therefore, Xiaoming has to pay 5 yuan, Xiaohai 20 yuan and Xiaoqiang 12 yuan

Cuboid carton, length, width and height are 5cm, 4cm and 3cm respectively. What's the surface area of this carton? What's its volume? What's the sum of its edge length
How many cm is it

Surface area = (L * W + L * H + h * W) * 2 = (5 * 4 + 5 * 3 + 4 * 3) * 2 = 94 square centimeters
Volume = L * w * H = 5 * 4 * 3 = 60 CC
Sum of edge length = (length + height + width) * 4 = 48CM