Let the sum of the first n terms of the sequence {an} be Sn, let TN = (S1 + S2 +... + SN) / N, and call tn the "average sum" of the sequence A1, A2,... An It is known that the average sum of series A1, A2,. A500 is 2004, then the average sum of series A1, A2,..., A500 is 2004 Sorry, I missed it. It's the average sum of series 2, A1, A2,... A500

The question is wrong,
The two sequences are the same
If it is: X, A1, A2 , a 500
The result is x + 2004 * 500 / 501 = x + 2000

For a square, the side length is a centimeter. If the side length is increased by 1 centimeter, then the current perimeter is 12 centimeters. What is a?

From the meaning of the question, (1 + a) × 4 = 12 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 1 + a = 3 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; a = 2; a is 2

6 / 0.75 reduction ratio

6:0.75
=(6×4）：（0.75×4）
=24:3
=8:1

Let x1, X2, x3.xn be positive numbers, and prove: X1 ^ 2 / x2 + x2 ^ 2 / x2 +. + XN-1 ^ 2 / xn + xn ^ 2 / X1 > = X1 + x2 + X3 +. + xn

The most direct is to use Cauchy inequality to get: (x2 + X3 +... + xn + x1) (x1 ^ 2 / x2 + x2 ^ 2 / X3 +... + X (n-1) ^ 2 / xn + xn ^ 2 / x1) ≥ (x1 + x2 +... + X (n-1) + xn) ^ 2. Divide both sides by x2 + X3 +... + xn + X1 = X1 + x2 +... + X (n-1) + xn

A family kitchen needs 480 tiles of the same specification of a certain brand. The tiles sold in the decoration material store are packaged in large and small packages. The large package is 50 pieces per package, and the price is 30 yuan; the small package is 30 pieces per package, and the price is 20 yuan?

According to the meaning of the question, there are three purchase schemes. Scheme 1: only buy large package, you need to buy 48050 = 485 packages. Because there is no folding package, you only need to buy 10 packages, and the cost is 30 × 10 = 300 yuan. Scheme 2: only buy small package, you need to buy 48030 = 16 packages, and the cost is 16 × 20 = 320 yuan

Kirchhoff's law of voltage
The title of the book is independent power supply and resistance in series. The power supply has a reference direction but the resistance does not. If you want to calculate the resistance voltage U = I × R or - I × R, do you want to assume that the resistance voltage is connected with the current
Elder and elder students, answer quickly

Resistance is a load, not an energy source, so there is no reference direction. Generally, the reference direction is current. As for whether the voltage is positive or negative, it depends on the reference point. For example, suppose that in a DC circuit, the positive pole of the power supply is connected to resistance a, the negative pole of the power supply is connected to resistance B, and the current flows to B through point a

The domain of y = arcsinx / 3 + LNX / X – 2

Is this the order of parentheses? Y = (arcsinx) / 3 + (LNX) / X – 2
Then the domain 0

Divide a circle into 16 parts averagely and make it into an approximate rectangle. The perimeter of the rectangle is 8 cm longer than that of the original circle. The area of the original circle is______ Square centimeter

The radius of the circle: 8 △ 2 = 4 (CM), the area of the circle: 3.14 × 42 = 50.24 (square cm), answer: the area of the original circle is 50.24 square cm, so the answer is: 50.24

How many grams is 0.025 Jin?

0.025 times 500 = 12.5g

In order to get the image of the function y = 2cos (x + π / 6) sin (π / 3-x) - 1, we only need a simple method to find the function y = 1 / 2sin2x + √ 3 / 2cos2x

The function y = 2cos (x + π / 6) sin (π / 3-x) - 1
=2cos(x+π/6)sin[ (π/2-((x+π/6)) ]-1
=2cos(x+π/6) cos(x+π/6)-1
=2cos²(x+π/6)-1
= cos(2x+π/3),
y=1/2sin2x+√3/2cos2x
=sin(2x+π/3)
=cos(π/2-2x-π/3)
=cos(2x-π/6)
=cos[2(x-π/12)]
y=cos(2x+π/3)
=cos[2(x+π/6)]
The image of y = 1 / 2sin2x + √ 3 / 2cos2x can be shifted to the left by π / 6 - (- π / 12) = π / 4