The sinusoidal AC circuit is shown in Figure 1-19. Given that the readings of ammeter A1, A2 and A3 are 1a, 3a and 5A respectively, the reading of master meter a is? Why?

The sinusoidal AC circuit is shown in Figure 1-19. Given that the readings of ammeter A1, A2 and A3 are 1a, 3a and 5A respectively, the reading of master meter a is? Why?

The current of a is equal to I1 + I2 + I3, which means that the vectors are added, so the direction A3 is downward, the direction A1 is upward, and the added resistance is downward 4. The resistance direction is horizontal, so after adding, the reading of a is 5A

As shown in Figure 1-2, in the sinusoidal current circuit, the readings of the known ammeter are a1:5a, a2:20a and a3:25a respectively

A=(A1^2+(A2-A3)^2)^0.5=(25+25)^0.5=5*2^0.5=7.07A

Given a + B = 2, then the value of (1 / 2) a & # 178; + (1 / 2) B & # 178; + AB is——————

(1 / 2) a & # 178; + (1 / 2) B & # 178; + ab
=1/2(a+b)²
=1/2*4
=2

5 x square plus 6 x minus 7 equals 0

5x²+6x=7
x²+6x/5=7/5
x²+6x/5+9/25=7/5+9/25
(x+3/5)²=44/25
x+3/5=±2√11/5
x=(-3-2√11)/5,x=(-3+2√11)/5

Solution equation: (x-1 / 2) - (1-x / 1) = 3
Urgent need

2/(x-1) - 1/(1-x) = 3
3/(x-1)=3
x-1=1
x=2

Vector group (1) A1, A2, A3 (2) A1, A2, A3, A4 (3) A1, A2, A3, A5 R (1) = R (2) = 3, R (3) = 4, proving that the rank of vector group A1, A2, A3, A5, - A4 is 4

R (A1, A2, A3) = 3,) A1, A2, A3 are linearly independent, R (A1, A2, A3, A4) = 3, A1, A2, A3, A4 are linearly correlated
A 4 is a linear combination of a 1, a 2 and a 3
R (A1, A2, A3, A5) = 4, A1, A2, A3, A5 are linearly independent
Obviously, R (A1, A2, A3, a5-a4) can only be 3 (∵ A1, A2, A3 are linearly independent, R ≥ 3), or 4 (n = 4. R ≤ 4)
If R (A1, A2, A3, a5-a4) = 3, then A1, A2, A3, a5-a4 are linearly correlated
From the "irrelevance representation theorem", a5-a4 is a linear combination of A1, A2 and A3, while A4 is a linear combination of A1, A2 and A3
A5 = (a5-a4) + A4 is also a linear combination of A1, A2 and A3. According to the equivalence theorem of expressible correlation, A1, A2, A3 and A5 are linearly correlated
It has no linear relationship with A1, A2, A3 and A5. R (A1, A2, A3, a5-a4) = 4

Solution equation: 0.6x + x = 70

1.6x=70

A group of mutually unequal rational numbers x1, X2, X3, x4, X5 arranged from small to large, and each number is less than - 1, then 1, x1, - X2, X3, - x4, X5 are used

,x1

If the polynomial x2 + MX + 16 = (x-4) 2, then the value of M is______ ．

∵ (x-4) 2 = x2-8x + 16, ∵ M = - 8

As shown in the figure. De is the median line of triangle. ABC. Point F is on De, and

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