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It is known that the image of quadratic function intersects with X axis at points a (x1,0), B (x2,0) (x1 < x2), where x1, X2 are related to X Where x1, X2 are the two roots of the equation x & # 178; + 2 (m-1) x + 2m & # 178; - 23 of X. and the distance from the image vertex P of the quadratic function X1 & # 178; + x2 & # 178; = 26 to the X axis is 9! (1) Find the value of M; (2) find the coordinates of a and B; (3) find the analytic expression of the quadratic function
1.x²+2(m-1)x+2m²-23=0
x1+x2=2(1-m)
x1x2=2m²-23
x1²+x2²=(x1+x2)²-2x1x2
Substituting into numerical calculation, M = 3
2. x1+x2=-4
x1x2=-5
Another x1
What curve does equation x ^ 2 / (sin √ 2-sin √ 3) + y ^ 2 (COS √ 2-cos √ 3) = 1 represent
Because √ 2 + √ 3 > π, there are:
(sin√2-sin√3)=2cos(√2+√3)/2sin(√2-√3)/2>0
(cos√2-cos√3)=-2sin(√2+√3)/2sin(√2-√3)/2>0
So the equation represents an ellipse
It is known that α belongs to [0, π / 2]. When the value of α changes, the equation x ^ 2 × sin α + y ^ 2 × cos α = 1 represents the shape of the curve
If α belongs to [0, π / 2], then sin α and cos α are both greater than 0 and less than 1; if α = 0, sin α = 0, cos α = 1, and the equation is y ^ 2 = 1, then y = ± 1 is two straight lines parallel to the X axis; if α ∈ (0, π / 4), sin α < cos α is an ellipse with focus on the X axis; if α = π / 4, sin α = cos α = √ 2 / 2, and the center is at the origin
When a mole of sodium and a mole of aluminum are put into a sufficient amount of water, the density of the solution is dg / ml, and the mass fraction of solute in the solution is?
2Na+2H2O=2NaOH+H2 2Al+2NaOH+2H2O=2NaAlO2+3H2
2 2 1 2 2 2 3
a a a/2 a a a 1.5a
The final solute is NaAlO2 amol mass 82a g, solution mass = 23a + 27a + m-4a = 46a + M
Mass fraction = 82a / (46a + m) * 100%
1. Calculation formula of small scale VAT payable: Sales of this month / (1 + 3%) * 3%
2. Calculation formula of VAT paid by general taxpayers: Sales of this month / (1 + 17%) * 17%
The calculation formula of monthly VAT should be like this, right? I want to confirm it
If you know, please answer. Thank you
Small scale industrial enterprises and commercial enterprises are calculated like this
If the tax is not included, the sales amount is directly multiplied by the applicable tax rate
The input tax can be deducted from the output tax when the general taxpayer pays the value-added tax. Another is that the value-added tax and the sales amount are indicated in the general VAT special invoice, and the sales amount is the sales amount excluding tax. The general VAT invoice does not indicate that the sales amount includes tax. If you want to calculate the value-added tax, you need to use: this month's sales amount / (1 + 17%) * 17%
When the voltage at both ends of a fixed value resistor is 4V, the current passing through it is 0.5A, and the resistance value of the fixed value resistor is______ Ω, if 4V is added at both ends of the resistor, the current passing through the resistor is______ A. If there is no voltage at both ends, the current passing through is______ A. At this time, the resistance value of the constant resistance is______ Ω．
∵ I = ur, ∵ resistance value: r = UI = 4v0.5a = 8 Ω; when the voltage increases by 4V, that is, the voltage is 8V, the current through the conductor: I '= u' r = 8v8 Ω = 1A; when the voltage is 0, the current through the conductor is 0A, the conductor resistance is independent of the voltage, and when the voltage is zero, the resistance is still 8 Ω; so the answer is: 8; 1; 0; 8
8 observe the following formulas 1 & sup2; + 1 = 1 * 2, 2 & sup2; * 2 = 2 * 3, 3 & sup2; * 3 = 3 * 4 Please use natural number n (n ≥ 1) to express the rule you guess
If n is a positive integer, try to explain that the value of n (2n + 1) - 2n (n-1) must be a multiple of 3
First simplify and then evaluate
X & sup2; (3-x) + X (X & sup2; - 2x) + 1, where x = radical 3
Given 2x-3 = 0, find the value of algebra x (X & sup2; - x) + X & sup2; (5-x) - 9
A rectangular iron sheet, 5 A & sup2; + 4 B & sup2;) m long and 6 A & sup2; m wide, subtracting a small square with side length of 3 / 2 A & sup2; m from its four corners, and then folding it into a box without cover to calculate the volume of the box
N & sup2; + n = n (n + 1) n (2n + 1) - 2n (n-1) = 3N, so it must be a multiple of 3 x & sup2; (3-x) + X (X & sup2; - 2x) + 1 = x & sup2; + 1 primitive = (√ 3) & sup2; + 1 = 4x (X & sup2; - x) + X & sup2; (5-x) - 9 = 4x & sup2; - 9 = (2x-3) (2x + 3) = 0 (5a & sup2; + 4B & sup2; - 3 /
An electric lamp, an ammeter and a resistor are connected in series in the circuit, and a voltmeter is connected in parallel at both ends of the resistor
What will happen to the ammeter and voltmeter when the resistance is short circuited
The resistance is short circuited. The resistance is equal to a wire. The voltmeter is connected in parallel at both ends of a wire. It measures the voltage at both ends of the wire. The voltage of each part of the parallel circuit is divided by the proportion of the resistance value of the part in the total resistance of the whole circuit. The resistance of the wire is extremely small, infinitely close to zero, so the voltage is also very small, so the voltage representation becomes small, It's close to zero. The circuit is still a loop, but the resistance is equal to a wire. The whole circuit loses the resistance value. If the total resistance changes, the total current will increase. The ammeter is connected in series in the circuit, and the total current will be measured, so the current indication will increase
How to solve equation 14 + (4.8x-6) - 2.8x = 8
14+(4.8x-6)-2.8x=8
14+4.8x-6-2.8x=8
8+2x=8
2x=0
x=0
If the voltage is u and the current of the resistance Rb in the power supply is I, then the open circuit voltage of the battery is as follows:
A.E＝U＋Rb＊I
B.E＝U－Rb＊I
C.U
answer
B
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