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

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

∵ B, m, a and B, N, C are two arithmetical sequences, ∵ M-B = A-M, N-B = C-N, ∵ M = a + B2, n = B + C2; ∵ a, B, C are arithmetical sequences, let the common ratio be q, then B = AQ, C = aq2, ∵ am + CN = AA + B2 + CB + C2 = 2AA + AQ + 2aq2aq2 = 21 + Q + 2q1 + q = 2 + 2q1 + q = 2 + 2q1 + q = 2

I have two math problems about arithmetic and arithmetic,
1. The equation 2x ^ 2 + MX + n = 0 has real roots, and 2, m, n are the first three terms of the arithmetic sequence, so the range of tolerance D of the arithmetic sequence can be obtained
2. The known sequence satisfies A1 = 7 / 8, a (n + 1) = 1 / 2 * an + 1 / 3, and N is a positive integer
(1) Prove: {An-2 / 3} is an equal ratio sequence
(2) Finding the general term formula of sequence {an}
(Note: A1, a (n + 1), an means that the subscript of a is 1, N + 1, n)
Can you answer the second question in more detail? Holiday for a long time did not write the question, the brain is a bit confused, ha ha.

If 1.2x2 + MX + n = 0, then △ = M2-4 * 2n ≥ 0 (1), if 2, m, n are arithmetic sequence, then 2m = n-2 (2), then m2-8 (2m + 2) ≥ 0 → (M-8) 2 ≥ 80 → m ≥ 4 √ 5 + 8 (2), if d = m-2, then d ≥ 4 √ 5 + 6

Let Sn be the sum of the first n terms of the arithmetic sequence {an}, if A5 / A3 = 5 / 9, then S9 / S5 =:
A 1 B -1 C 2 D 1/2
Please explain why

S9/S5=(9a5)/(5a3)=1
Choose a

Find the function f (x) = x2 + 2 (m-1) x + 2, where x is less than or equal to 4 is a monotone decreasing function, and the value range of M is?

The axis of symmetry x = 1-m, the opening is downward, and the left side of the axis of symmetry is a decreasing function
∴1-m>=4
So m

As shown in the figure, take sides AC and BC of △ ABC as one side respectively, and make square ACDE and cbfg outside △ ABC. Point P is the midpoint of EF. Prove that the distance from point P to AB is half of ab

Then Er ∥ PQ ∥ FS, ∵ P is the midpoint of EF, ∥ q is the midpoint of RS, ∥ PQ is the median line of trapezoidal EFSR, ∥ PQ = 12 (ER + FS), ∥ AE = AC (equal side length of square), ∥ aer = ∥ cat (equal residual angle of the same angle), ∥ r = ∥ ATC = 90 °, ∥ RT △ aer ≌ RT △ cat (AAS), the same as RT △ BFS ≌ RT △ CB T，∴ER=AT，FS=BT，∴ER+FS=AT+BT=AB，∴PQ=12AB．

It is proved that the remainder of F (x) = 2x ^ 2 + 7x + 9 divided by ax + B is positive
A and B are not mentioned, but press 2 and 7 first
By the way, the remainder (negative ／ positive, positive ／ negative, negative ／ negative) thank you

Theorem: the sign of the remainder is consistent with the divisor
So the divisor is reduced to = 2 (x + 7 / 4) ^ 2 + 23 / 8, which is always positive, so the remainder is also positive

A is the smallest positive integer, B is the opposite of the largest negative integer, and C is the number represented by the point with the smallest distance from the number axis to the origin. Find the value of a + 2B + C

From the title, a = 1, B = - 1, C = 0
Then a + 2B + C = 1-2 + 0 = - 1

If 5an-1b2 and - 3a3bm are similar, then M=______ ，n=______ ．

∵ 5an-1b2 and - 3a3bm are of the same kind, n-1 = 3, M = 2, the solution is m = 2, n = 4

How to connect the 380V heating tube with 220V power supply

Add a 220 V step-up 380 V transformer, and cut the resistance wire short

General division X / a (X-Y), Y / b (Y-X)

x/a（x-y）=- xb/-ab（x-y）
y/b（y-x）=ay/-ab（x-y）