If a, B and C are triangles, it is proved that: [A & sup2; + B & sup2; - C & sup2;] & sup2; - 4A & sup2; B & sup2; must be negative It's a math problem. About formula method

If a, B and C are triangles, it is proved that: [A & sup2; + B & sup2; - C & sup2;] & sup2; - 4A & sup2; B & sup2; must be negative It's a math problem. About formula method

If a, B and C are the three sides of a triangle, it is proved that (A & sup2; + B & sup2; - C & sup2;) & sup2; - 4A & sup2; B & sup2; must be negative

The following: (A: (a) \\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\35;178; - 2Ab) = [(a + b) & #178; - C & #178;] [(a-b) & #178;]

What is the magnetic field produced by an infinite wire?
Some say it's ki / R, some say it's μ I / 2 π R
k=μ/4π
Which is right?

That's right
B = (U / 2 open) I / r = UI / (2 open)

Isn't it said that the changing electric field produces a magnetic field? Then why can a constant current produce a magnetic field? Is it to make the wire micro element?

That's how it works
The current is composed of moving charges. Even if it is a constant current, from the perspective of micro motion, it is composed of groups of charges moving at a constant speed, and each charge itself has an electric field. When the charge moves, the electric field moves, but the charge quantity of the charge remains unchanged, so the electric field changes only in the direction, but the size remains unchanged. Therefore, a constant current is equivalent to a uniform electric field, A uniform electric field produces a constant magnetic field
Please advise!

Why does the magnetic field generated by an electrified straight wire increase when its current increases?
Is there a formula for this?

For an electrified wire (straight wire of course), the magnetic induction intensity of the magnetic field generated at a distance of R from the wire is b = k * I / R
Where k is a constant and I is the current on the wire
Obviously, for a certain distance from the wire, the greater the current of the electrified wire, the greater the magnetic induction B of the point

Why does the reverse current change when the magnetic field acts on the conducting wire

The direction of the current depends on the connection of the positive and negative poles of the power supply. This can be changed completely. I don't know if you are asking this question. The direction of the force on the conductor and the direction of the magnetic field are related to the direction of the current. When only one of the two directions is changed, the direction of the received force changes. When both directions are changed at the same time, the direction of the received force remains unchanged
Don't know how to ask me

What does the power cable model ykw22-5 * 75 mean

Copper core XLPE insulated PVC sheathed control cable with armor for rated voltage of 5 / 75 kV
5 / 75 means:
"Rated voltage 5 / 75KV" - Application / voltage level
　y:　
"Copper core" -- conductor material
　　
"Cross linked PVC insulation" -- insulating material
KW22:　　
"With armor" -- material and type of armor layer (double steel strip gap wrapping)
　　
"PVC sheath" - inner and outer sheath material

What does the cable model gm-yjv-4 * 120 + 1 * 75 / 4 * 70 + 1 * 35 mean

Four sets of coils with 120W in each group plus 75W starting winding
As for the 4 * 70 + 1 * 35, it means using 100Hz power

What is zryjv-2 (4 * 120 + 1 * 50) cable

The front 2 represents: steel strip armor
3: Thin steel wire armour
4: Thick steel wire armour

Excuse me, what do the letters and numbers of power cable 2bv1 * 10 mean?

2BV: Double PVC insulated cable
1 * 10:1 core, cross-sectional area of 10mm2