On the phase difference of alternating current When the angular frequency of two alternating current is different, can you judge its phase difference? Can you talk about the specific reasons of "can" and "can't"? If you know, I hope you can give me your advice!

When the angular frequency of two AC power sources is different, the phase difference between them is always changing, so only the instantaneous phase difference can be measured, there is no relatively stable phase difference, so the answer can not be given

Two sinusoidal alternating current, the initial phase is 90 degrees, their phase difference is how many degrees

360

According to this rule, the nth figure is more than the (n-1) figure___ A chess piece

Let the number of pieces of the nth figure be SN. For the first figure, S1 = 1; for the second figure, S2 = 1 + 4; for the third figure, S3 = 1 + 4 + 7; then the nth figure has (3n-2) more pieces than the (n-1) figure

Discussion on quadratic function in the third grade of junior high school
In plane rectangular coordinates, the vertex of quadratic function image is a (1, negative four) and passes through B (3,0)
Question: (1) find the analytic expression of the quadratic function
(2) If the image of the quadratic function is shifted several units to the right, the translated image can pass through the coordinate origin. Try to write out the coordinate of the intersection of the translated image and the x-axis directly
[Wuwuwuwu, I'm sorry, I only have 15 drops of money. I've been asked all the time. If I don't think the children's shoes I asked are enough, I'll go to collect money later Wuwu, just ask me to answer this question 】

y=（x-1）^2-4
Move one unit over (4,0)

Given the function y = 2 / 2x square - 3x + 2 / 3 (1), write the value range of the independent variable x (2) write the highest point of the function image
(2) What is the value of coordinate (3) x at the point of intersection with X axis, y decreases with the increase of X?

Y=1/2X^2-3X+3/2
=1/2(X^2-6X+9-9)+3/2
=1/2(X-3)^2-2
(1) x is all real numbers,
(2) lowest point: (3, - 2)

（a2-2ab+2b2)-(2a2-2ab-3ab2)
Simplification

（a²-2ab+2b²)-(2a²-2ab-3ab²)
=a²-2ab+2b²-2a²+2ab+3ab²
=-a²+2b²+3ab²

It is known that ad is the outer bisector of △ ABC, and E is any point on ad connecting EB and EC

Take a point F on the extension line of Ca, let AF = ab
The congruence of △ AEF and △ AEB (AB = AF, ∠ EAB = ∠ EAF)
So EF = be
In triangle CEF
EC+EF=EC+BE＞CF=AF+AC=AB+AC

How many hectares is one square decimeter

1 hectare = 10000 square meters = 10 ^ 6 square decimeters, so 1 square decimeter = 0.000001 hectare

The average length of the top and bottom of a trapezoid is 30 cm high and 20 cm. The area of this trapezoid is () square cm

30x2 = 60, (30 + 30) X20 / 2 = 600

A triangle with a circumference of 12 cm has a set,

A, B, C | a > 0, b > 0, C > 0, a + B + C = 12, a + b > C, a + C > b, B + C > A

On the phase difference of alternating current When the angular frequency of two alternating current is different, can you judge its phase difference? Can you talk about the specific reasons of "can" and "can't"? If you know, I hope you can give me your advice!