The multiplication of the first 50 natural numbers is 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11. + 47 + 48 + 49 what is the answer Wrong, it's 0 * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10... * 47 * 48 * 49

The multiplication of the first 50 natural numbers is 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11. + 47 + 48 + 49 what is the answer Wrong, it's 0 * 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10... * 47 * 48 * 49

Using Gauss formula, we can get the original formula = (1 + 49) × 49 △ 2 = 1225
Because there is a zero in the factor

If there are three fixed value resistors in parallel in the circuit, and their resistance ratio R1: R2: R3 = 1:3:5, then the current ratio I1: I2: I3 passing through them is ()
A. 1：3：5B. 15：5：3C. 5：3：1D. 5：3：15.

∵ R1: R2: R3 = 1:3:5, ∵ R1 = 1 Ω, R2 = 3 Ω, R3 = 5 Ω can be set, ∵ the voltage at both ends of each branch in parallel circuit is equal, ∵ according to Ohm's law, we can get: I1: I2: I3 = ur1: UR2: UR3 = 11 Ω: 13 Ω: 15 Ω = 15:5:3

Each bus is limited to 40 people, while the passenger car is limited to 30 people. We have 80 people going out to play. Is it enough to rent these two cars

This is a simple math problem. There are 80 people in total (one car takes 40 people and the other only takes 30 people). How can two cars only take 70 people? Why don't you rent two buses that can take 40 people? (for reference)

How many square kilometers is "5 square meters" equivalent to 20 hectares

1 ha = 0.01 km2
1 square meter = 1 * 10-6 square kilometers (0.0000001)
So 20 hectares 5 square meters = (0.2 + 0.000005) = 0.200005 square kilometers

How to calculate the matrix with unknowns in MATLAB?
The coefficient matrix of a system of equations contains unknowns. How to express the matrix with unknowns in MATLAB?

Just define a symbol matrix with sym
The format is sym (']');
Coefficient matrix in

What kind of thoughts and feelings does you Baishui express

It expresses the author's closeness and love for nature
Su Shi was exiled again when he was 58 years old. He was placed in Huizhou (now Huizhou, Guangdong Province) as the vice envoy of Ningyuan army. He arrived in Huizhou in October of the first year of Shaosheng (1094). He visited Baishui mountain on the 12th and wrote this essay. The random records show the local scenery and the old man's feeling of being at ease and enjoying himself

Sin (2x + y) = 3siny, X ≠ K π + π / 2, x + y ≠ K π + π / 2 (K ∈ z): Tan (x + y) = 2tanx

Conclusion Tan (x + y) = 2tanx and sin (2x + y) = 3siny
From the angle of view, we can see
2x+y=(x+y)+(x)
y=(x+y)-(x)
In this way, the conclusion can be deduced from the condition
The condition becomes
3sin [(x + y) + x] = sin [(x + y) - x] - according to the sum of two angles formula of trigonometric function sin (α + β) = sin α cos β + cos α sin β
Sin (α - β) = sin α cos β - cos α sin β
3sin (x + y) cosx-3cos (x + y) SiNx = sin (x + y) cosx + cos (x + y) SiNx
2sin(x+y)cosx=4cos(x+y)sinx
Because x ≠ K π + π / 2, cosx ≠ 0
Because x + y ≠ K π + π / 2, cos (x + y) ≠ 0
Then, divide both sides by cos (x + y) cosx to get
tan(x+y)=2tanx

The square of (2a + 1) multiplied by the square of (2a-1) becomes the complete square formula

（4a²-1）²

I want to be a pig and live a simple and happy life

I want to be a pig,living a simple and happy life.
Make sure it's right

How much is a 15% drop in price

15 * (1-15%) = 12.75 yuan
Price 15 yuan, 15% reduction is equal to 12.75 yuan
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