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a. The sum of the three numbers is 12, and A-1, B, C + 10 are equal ratio series Big brother, I can guess the numbers
2,4,6 or 17,4, - 9
b=4,a=8-c
∴（a-1)(18-a)=16
Let a
a/b=b/c
a+b+c=3
We can know 3B = 3, B = 1 by arithmetic sequence
According to the first formula, AC = 1
Then a + 1 / a = 2, a = 1, C = 1,
Also a
If the second, third and sixth items of the arithmetic sequence with tolerance not 0 constitute the arithmetic sequence, then the common ratio is______
a2*a6=a3^2
(a1+d)(a1+5d)=(a1+2d)^2
a1^2+6a1d+5d^2=a1^2+4a1d+4d^2
2a1d = - D ^ 2, tolerance is not 0
d=-2a1
q=a3/a2=(a1+2d)/(a1+d)
=(a1-4a1)/(a1-2a1)
=-3a1/(-a1)
=3
It is known that four real numbers - 9, A1, A2 and - 1 are equal difference sequences, and five real numbers - 9, B1, B2, B3 and - 1 are equal proportion sequences, then B2 (a2-a1) = ()
A. 8B. -8C. ±8D. 98
From the question, we get a & nbsp; 2 − A & nbsp; 1 = D = − 1 + 94 − 1 = 83, B22 = 9, and because B2 is the third term in the equal ratio sequence, it has the same sign with the first term, that is, B2 = - 3 B2 (a2-a1) = - 8
|If A-2 | and (a + 2b) &# 178; are opposite to each other, what is (b) &# 178; △ a equal to
How to measure the actual power of a 220 V 60 W incandescent lamp when it is connected to a home circuit
Turn off all the other appliances and watch the meter turn a few times
Rewrite 6.25 to the following number. What's the change of its size? 62.50.625 6250.0625
62.5 is 10 times of 6.25
625 is 0.1 times of 6.25
625 is 100 times of 6.25
0625 is 0.01 times of 6.25
Connect two resistors R1 = 15 ohm and R2 = 5 ohm in series to the power supply, and the voltage at both ends of R1 is 3V
The voltage at both ends of R2 is________ 5. The power supply voltage is______ V.
Because R1 and R2 are connected in series, there are:
UR1：UR2＝R1：R2,
So UR2 = ur1xr2 / R1 = 1V,
The power supply voltage is ur1 + UR2 = 1 + 3 = 4V
A simple algorithm of 17 × 15:14 × 17:7 × 28:5
17×14/15 × 7/17 × 5/28
=（17× 7/17） ×（14/15×5/28）
＝7×1/6=7/6
There is an ammeter with internal resistance Rg = 30 and full bias current Ig = 1mA. If you want to refit it into a voltmeter with a range of 0-3v, how much resistance should be connected in series? After refitting, it will be electrified
Full bias current Ig = 1mA, refit into a voltmeter to series a large resistance, how big, calculate. The maximum voltage divided by the full bias current is OK, r = 3V / 1mA = 3000 ohm, and because the original RG = 30, so as long as the series 3000-30 = 2970 ohm resistance is OK
RELATED INFORMATIONS
- 1. If A1, A2, A3 are known to be an arithmetic sequence, B1, B2, B3 are known to be an arithmetic sequence, and these six numbers are all real numbers, then the correct conclusion in the following four conclusions is () ① A1a3 may be established at the same time; ② B1 < B2 and B2 > B3 may hold simultaneously ③ If a1 + A2
- 2. It is known that four real numbers - 9, A1, A2 and - 1 are equal difference sequences, and five real numbers - 9, B1, B2, B3 and - 1 are equal proportion sequences, then B2 (a2-a1) = () A. 8B. -8C. ±8D. 98
- 3. In ABC triangle, a = 2bcosc, judge what triangle is
- 4. In a right triangle ABC, the angle c = 90 ° and the side lengths a, B, C satisfy arcsin (1 / a) + arcsin (1 / b) = Pai / 2, and LGC = LGA + LGB
- 5. In the arithmetic sequence an, we know A1 = 3 / 2, d = - 1 / 2, Sn = - 15, find the sum of N and an
- 6. The square of B = AC is ()
- 7. If B ^ 2 = a C = 9, then B is equal to 3 or a 3, there is only one answer
- 8. It is known that the sum of the three positive numbers in the arithmetic sequence is equal to 15, and the three positive numbers are added with 9 in turn, then they are in the arithmetic sequence, and the three positive numbers are solved
- 9. The extremum of higher number. Y = 2x to the third power - 6x square - 18x + 7
- 10. Where is the stationary point of the cubic power of y = 2x - 6x square - 18x + 73 Where 6x square - 12x - 18 comes from? I don't know what derivative is
- 11. It is known that a and B are two unequal positive numbers, and a, x, y and B are in equal difference sequence in turn, and a, m, N and B are in equal proportion sequence in turn. Try to compare the size of X + y and M + n
- 12. Isochromatic In the known equal ratio sequence {an}, A3 = 16, common ratio q = 1 / 2 Q: if the sum of the first n terms of the sequence {an} is Sn = 124, find the value of n The first n terms of {an} and Sn = - 2n ^ - n are known Ask: seek a1 + a3 + A5 + +The value of a25
- 13. It is known that a, B and C are equal ratio sequence, B, m, a and B, N and C are two equal difference sequence, then am + CN = () A. 4B. 3C. 2D. 1
- 14. X-8 / 5x = 48 solution equation
- 15. Detailed process of solving equation: 0 = - 1 / 16 (x-4) ^ 2 + 3
- 16. The tangent equation of curve y = 2x + 1 / X at point (1,3) is? Finally, there are steps, The tangent equation of y = 2x + (1 / x) at point (1,3) is
- 17. AB is the diameter of the circle O, C is a moving point on the semicircle, CD ⊥ AB connects Co, CP bisects ∠ OCD, does the position of P change with the position of C?
- 18. If the function f (x) = asinx bcosx (AB ≠ 0) has f (π / 4-x) = f (π / 4 + x) for any real number x, then the slope of the line ax-2by + C = 0 is
- 19. Fill the nine numbers - 2, - 1, 0, 1, 2, 3, 4, 5 and 6 into the nine spaces of the square matrix, so that the sum of the three numbers in the horizontal, vertical and diagonal angles is 6
- 20. Simple calculation of 1105 / 18 * 72 = 4 420