Sequence and Series Flashcards
1
Q
General term of the arithmetic progression
A
an = a+(n-1)d
2
Q
Sum of terms in AP
A
sn = n/2{2a + (n-1)d}
3
Q
3 no. in AP
A
a-d, a, a+d
4
Q
4 no. in AP
A
a-3d, a-d, a+d, a+3d
5
Q
5 no. in AP
A
a-2d, a-d, a, a+d, a+2d
6
Q
Arithmetic Mean of two numbers
A
a+b/2
7
Q
General term of the GP
A
ar^(n-1)
8
Q
3 no. in GP
A
a/r, a, ar
9
Q
4 no. in GP
A
a/r^3, a/r, ar, ar^3
10
Q
5 no. in GP
A
a/r^2, a/r, a, ar, ar^2
11
Q
Sum of terms in a finite GP
A
a(1-r^n)/(1-r)
12
Q
Sum of terms in an infinite GP
A
a/1-r
13
Q
Geometric Mean of two numbers
A
root a*b
14
Q
Harmonic Mean of two numbers
A
2ab/a+b
15
Q
Relation between A.M., G.M. and H.M.
A
A.M.*H.M. = (G.M.)^2
