1
Q
AP
Tn
Sn
A
Tn= a+(n-1)d
Sn= n/2 [2a(n-1)d]
Or
n/2 (a+l)
2
Q
GP
Tn
Sn
A
Tn= ar^(n-1)
Sn= a(r^n -1)/r-1 r>1
Sn= a( 1-r^n) / 1-r r<=1
3
Q
Assumption terms
AP
A
3•••••• (a-d) a (a+d)
4•••••• (a-3d) (a-d) (a+d) (a+3d)
5••••••(a-2d) (a-d) a (a+d) (a+2d)
4
Q
GP
Assumption terms
A
3 terms•••••••• a/r, a, ar
4 terms•••••••• a/r^3 a/r ar a ar^3
5 terms•••••••• a/r^2 a/r a ar ar^2
5
Q
AM GM HM
A
Terms AM. GM. HM
- a+b/2. √ab. 2ab/ a+b
- a+b+c/3. 3√abc. 3abc/a+b+c
n. a+b+c…n/n. (abc…n)^1/n. 1/wtevr AP
AM>=GM>=HM
6
Q
Sum of frst n odd numbers
A
n^2
7
Q
Sum of first n even numbers
A
n(n+1)
8
Q
£n
A
n(n+1)/2
9
Q
£n^2
A
n(n+1)(2n+1)/6
10
Q
£n3
A
[n(n+1)/2]^2
11
Q
Infinite GP
A
S°° =a/1-r
