Progression AP, GP, sequences
Arithmetic Progressions (A. P.)
The sequence a , (a +d ), (a +2d ), (a +3d ), (a +4d ), . . . is called an arithmetic progression.
' a ' is the first term and ' d ' is the common difference of the A.P.
The nth term of the A.P. is a + ( n-1)d
numbers a , b, c are in A.P. if 2b = a +c.
Geometric Progression (G.P. )
Harmonic Progression (H.P.)