Free Study Material For RRB Examination: Mathematics (Sequences & Series)
Free Study Material For RRB Examination
Subject : Mathematics (Sequences & Series)
Arithmetic Progression (AP)
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If three terms are in AP, then they can be taken as (a – d), a, (a + d).
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If four terms are in AP, then they can be taken as (a – 3d), (a – d), (a + d), (a + 3d).
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If five terms are in AP, then they can be taken as (a – 2d), (a – d), a, (a + d), (a + 2d).
Geometric Progression (GP)
A geometric progression is a sequence in which terms increase or decrease by a constant ratio called the common ratio.
(i) The sequence 1, 3, 9, 27, 81…is a geometric progression whose first term is 1 and common ratio 3.
Harmonic Progression (HP)
If the reciprocals of the terms of a series form an arithmetic progression, then the series is called a harmonic progression.
