The expression of instantaneous value of a sinusoidal voltage is known as u = 380sin314t. Find its maximum value, effective value, frequency, period, angular frequency and initial phase angle

The expression of instantaneous value of a sinusoidal voltage is known as u = 380sin314t. Find its maximum value, effective value, frequency, period, angular frequency and initial phase angle

This is the basis of comparison. The maximum value um = 380V, the effective value ur = 380 / V 2 ≈ 220 V, the frequency f = 314 / (2 π) = 50 Hz, the period T = 1 / F = 1 / 50 = 0.02 s, the angular frequency w = 314, and the initial phase angle θ = 0

A sinusoidal AC voltage U = root 2 * sin (314T + 30 °) v. try to calculate the maximum, effective value and instantaneous value of the sinusoidal AC voltage when t = 0s

The maximum value is the root 2 when sin () = 1
The valid value is the maximum divided by the root 2, so it's 1
The instantaneous value is substituted by T = 0, which is equal to the root sign 2 divided by 2

1kg / M & # 179; how to = 1.0 * 10 negative cubic, 1g / cm & # 179; = 1.0 * 10 & # 179; kg / M & # 179; give a process analysis

1 g = 10 －3 kg ,1 cm3 = 10－6 m3 .
Put them into numerator and denominator respectively

We define a new operation "*" and specify that a * b = A & # 178; - 2b. For example, 2 * 3 = 2 & # 178; - 2 × 3 = - 2.2 * (- a) = 2 & # 178; - 2 × (- a) = 4 + 2A
If 3 * (- x) = 7, find the value of X
② If (- 2) * (2 * x) = 4 * (2x), find the value of X

1 、3*（-x）=7=9+2x
x=-1
2、（-2）*（2*x）=4*（2x）=(-2)*(4-2x)=4-8+4x=16-4x
x=2.5

The formula for the volume of a sphere?

Sphere volume v = 4 π R / 3

Which is the largest astronomical unit or light year?

Light years
An astronomical unit is the average distance from the sun to the earth
Light year is the distance light travels in a year

9999 2 / 3 + 999 2 / 3 + 99 2 / 3 + 9 2 / 3 + 1 / 3

9999 and 2 / 3 + 999 and 2 / 3 + 99 and 2 / 3 + 9 and 2 / 3 + 1 / 3 = (10000-1 / 3) + (1000-1 / 3) + (100-1 / 3) + (10-1 / 3) + (4 / 3) = 11110-4 / 3 + 4 / 3 = 11110

Proving Lagrange's mean value theorem with Rolle's theorem
I don't understand why a function is constructed by subtracting its chord from its curve in a closed interval. This is equivalent to drawing it into a curve function with the same end value and then onto the x-axis. The mathematical foundation is very poor. I hope not to say a lot. The formula is very complicated

Rolle's theorem needs two ends to be zero, so that the difference of ordinates between two ends is zero, which meets the requirements of Rolle's theorem

With two fifths of the length of the square cardboard are put together into a rectangle, the perimeter of the rectangle is () DM, the area is () square decimeters

You didn't write how many squares to spell?
If two pieces are used, the area will be twice of the original, that is: (2 / 5) ^ 2 * 2 = 8 / 25 square decimeters
After spelling, because there are two overlapping sides, the perimeter is equal to twice the perimeter of the small square, and then subtract the side length of the two squares
That is: (2 / 5) * 4 * 2 - (2 / 5) * 2 = 12 / 5 decimeter

Finding limit when x tends to infinity
Limx → & # 186; &# 186; (√ (x + √ (x + √ x)) / √ (3x + 1), I wonder if I have made it clear,

Support fate_ Results in June:
The root sign x has the same order as the root sign (3x), and the root sign (3x) is one order higher than the root sign (x),
The original formula is equivalent to √ X / √ (3x) = √ (1 / 3) = √ 3 / 3