an is known to be a series of equal differences, and a3 6, a6 0

1. an==a1+(n-1)d, then a3=a1+2d==-6, and a6==a1+5d=0, the connection equation gives a tolerance of 2, and the first term is -10, so an=2n-12

2. B1=-8, B2=-24, and {bn} is an equal difference series, as in the above question, the column equation is calculated to find the tolerance and the first term, you can know bn=-16N+8

1) Let the tolerance be d, then d=(a6-a3) 3=2, a1=a3-2d=-10 an=-10+2n (2) Let the tolerance be m, b2=a1+a2+a3=3a2=-24, and b1=-8 m=b2-b1=-16 So the general formula is -8+(-16)n=-8-16n So the sum of the first n terms is: [(8+-8-16n) 2] *n=-8n 2-8n

an};

10+2*(n-1)

bn|and formulas.

8*n^2

b1=-8, b2=—24, and {bn} is the difference series, as in the previous question, the column equation is calculated to find the tolerance and the first term, you can know bn=-16n+8

In the difference series, every two trillion cavity cherry numbers are one d apart, and the two are two different from each other

a5-a2=3d 3d=6

d=2a6=a3+3d＝7+6=13

a3+a6+a9=12

3a6=12

a6=4 a3a6a9=28

4-3d)*4*(4+3d)=28

The solution is d= 1

When d=1, a6=a1+5=4 is solved, a1=-1, and an=-1+(n-1)=n-2

When d=-1, a6=a1-5=4 is solved to obtain a1=9, at this time, the spine an=9-(n-1)=-n+10,9,an=3n-2,2,a3+a6+a9=(a+2d)+(a+5d)+(a+8d)=3a+15d=12 to obtain a+5d=4

a+2d)(a+5d)(a+8d)=28

Because a+5d=4

So (a+2d)(a+8d)=7

a^2+10ad+16d^2=7

4-5d) 2+10(4-5d)d+16d2=7 simplified to obtain d 2=1

d = plus or minus 1 when d >0 is matched with envy to the nucleus to sell infiltration d d = 1,0,

a4+a6=2a5=0

a5 = 0a5-2d) (a5 + 2d) = -16d = 21) when lead knows d d = 2.

a1=a5-4d=-8

sn=na1+n(n-1)d/2

n-9n2) when n=-2.

a1=a5-4d=8

sn=na1+n(n-1)d Huai book elimination 2

n+9n

In the difference series {Wang Changzhengan}, if a6=s3=12, find ana6=a1+5d=12

s3=a1+a2+a3=3a1+3d=12 to get d=2 a1=2

So an=a1+(n-1)d

2nYou are familiar with those repentant formulas!

1) Let the tolerance be d, then d=(a6-a3) 3=2, a1=a3-2d=-10

an=-10+2n

2) Set the tolerance of the spring tomato steak to x

b2=a1+a2+a3=3a2=-24

x=b2-b1=-16

So the general formula for hail roll is -8+(-16)n=-8-16n, so the sum of the first n terms is: [(8+-8-16n) 2] *n=-8n 2-8n