limx→∞4x^2+4x-3/3x^2-2x+1

limx→∞4x^2+4x-3/3x^2-2x+1

A:
LIM (x →∞) (4x ^ 2 + 4x-3) / (3x ^ 2-2x + 1) numerator and denominator divided by x ^ 2 at the same time
=lim(x→∞) (4+4/x-3/x^2) / (3-2/x+1/x^2)
=(4+0-0)/(3-0+0)
=4/3

Limx tends to 0 (2x-1) ^ 5 / ((2x + 1) ^ 2 (1-3x) ^ 2)

When x tends to 0, (2x-1) ^ 5 and (2x + 1) ^ 2 and (1-3x) ^ 2 are not equal to 0,
So we can directly substitute x = 0 into the calculation,
lim[x->0] (2x-1)^5/((2x+1)^2(1-3x)^2)
=(-1)^5 /1^2 *1^2
= -1

In the arithmetic sequence {an}, a1 + A2 = 7, A3 + A4 = 13, find A7 + A8

Because it's the arithmetic sequence {an}
So a1 + a3 = 2A2, A2 + A4 = 2A3
Add a1 + A2 = 7, A3 + A4 = 13
A1+A2+A3+A4=20
So 2A2 + 2A3 = 20
A2+A3=10
A1 + A2, A2 + a3, A3 + A4, A4 + A5 form the arithmetic sequence with tolerance of 3
So A7 + A8 = 25

In the arithmetic sequence {an}, if a1 + A2 = 3, A3 + A4 = 5, then A7 + A8 is equal to______ ．

Let the tolerance of arithmetic sequence {an} be D, then A3 + A4 = (a1 + 2D) + (A2 + 2D) = (a1 + A2) + 4D = 3 + 4D = 5, the solution is d = 12, so A7 + A8 = (A3 + A4) + 8D = 5 + 8 × 12 = 9, so the answer is: 9

In the arithmetic sequence {an}, a1 + A2 = 7, A3 + A4 = 13, then A7 + A8=

Because it's the arithmetic sequence {an}
So a1 + a3 = 2A2, A2 + A4 = 2A3
Add a1 + A2 = 7, A3 + A4 = 13
A1+A2+A3+A4=20
So 2A2 + 2A3 = 20
A2+A3=10
A1 + A2, A2 + a3, A3 + A4, A4 + A5 form the arithmetic sequence with tolerance of 3
So A7 + A8 = 25

1. In the arithmetic sequence {an}, a1 + A2 = 3, A3 + A4 = 6, a7 + A8

∵ a3 + a4 = （a1 + 2d）+ （a2 + 2d） = a1 + a2 + 4d ∴ （a3 + a4）-（a1 + a2） = （a1 + a2 + 4d）-（a1 + a2） = 6 - 3 = 3 = 4d ∴ d = 3 /...

Let {an} be an arithmetic sequence, and A1 minus A4 minus A8 minus A12 plus A15 = 2, find the value of A3 plus A13 and S15

Crab: a1-a1-3d-a1-7d-a1-11d + A1 + 14d = 2 ｛ a1 + 7d = - 2 ｛ A3 + A13 = a1 + 2D + A1 + 12D = 2 (a1 + 7D) = - 4
s15=a+(a+b)+...+(a+14b)=15a+105b=15(a+7b)=-30

In the arithmetic sequence, a1 + a3 + A8 = 15, A4 =?

a1+a3+a8=a12=3*a4=15,a4=5

In the arithmetic sequence {an}, A6 = A3 + A8, then S9=______ ．

Let the tolerance of {an} be D, and the first term be A1. From the meaning of the question, we can get that a1 + 5D = a1 + 2D + A1 + 7d, ｜ a1 + 4D = 0, S9 = 9a1 + 9 × 82d = 9 (a1 + 4D) = 0, so the answer is 0

In the arithmetic sequence {an}, A6 = A3 + A8, then S9=______ ．

Let the tolerance of {an} be D, and the first term be A1. From the meaning of the question, we can get that a1 + 5D = a1 + 2D + A1 + 7d, ｜ a1 + 4D = 0, S9 = 9a1 + 9 × 82d = 9 (a1 + 4D) = 0, so the answer is 0