## Important Concepts and Formulas - Sequence and Series

macoi

2015-06-18 12:35:06

mathematically speaking, the next term cannot be determined by giving only the first finite number of terms of a general sequence. explain this fact by giving examples

sani

2015-05-11 10:59:13

I hate sequence and series but after watching these formulas arrange in such an efficient manner i now i feel relaxed now i am not soooooooo much confuse so thanks.

Dev

2015-04-06 20:23:11

354/2 + 3 = 180

180/3 + 4 = 64

64/4 + 5 = 21

21/5 + 6 = 10.2

10.2/6 + 7 =

180/3 + 4 = 64

64/4 + 5 = 21

21/5 + 6 = 10.2

10.2/6 + 7 =

**8.7**
Apurv

2015-08-22 06:46:57

no formula

If a, b, c are in AP, 2b = a + c

Suppose a,b,c are in H.P. As reciprocals of A.P. are the terms in H.P,

@@\dfrac{2}{b}=\dfrac{1}{a}+\dfrac{1}{c}\\

\Rightarrow \dfrac{2}{b}=\dfrac{a+c}{ac}\\

\Rightarrow \dfrac{b}{2}=\dfrac{ac}{a+c}\\

\Rightarrow b=\dfrac{2ac}{a+c}@@

If a, b, c are in AP, 2b = a + c

Suppose a,b,c are in H.P. As reciprocals of A.P. are the terms in H.P,

@@\dfrac{2}{b}=\dfrac{1}{a}+\dfrac{1}{c}\\

\Rightarrow \dfrac{2}{b}=\dfrac{a+c}{ac}\\

\Rightarrow \dfrac{b}{2}=\dfrac{ac}{a+c}\\

\Rightarrow b=\dfrac{2ac}{a+c}@@

vishal

2014-12-17 16:55:18

Divide 20 into 4 parts which are in A.P. and such that the product of first and fourth is to product of the second and third in ratio 2:3

gandhi

2015-10-30 11:10:22

a-3d , a-d, a+d, a+3d

(a^2- 9d^2)/ (a^2-d^2) = 2/3

a/d=5

total = 20= 4a

a= 5

2, 4,6,8

(a^2- 9d^2)/ (a^2-d^2) = 2/3

a/d=5

total = 20= 4a

a= 5

2, 4,6,8

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