Math 5
Arithmetic Progression a, a + d, a + 2d, a + 3d, a + 4d, ………. ,a + (n – 1) d d = a 2 – a 1 = a 3 – a 2 = ……. = a n – a n – 1 nth Term of an AP :- a n = a + (n − 1) × d Sum of N Terms of AP:- S n = n/2[2a + (n − 1) × d] Sum of AP when the Last Term is Given :- S = n/2 (first term + last term) Geometric Progression a, ar, ar 2 , ar 3 , ar 4 ,…, ar n-1 Nth Term of G.P:- a n = t n = ar n-1 Sum of N term of GP:- S n = a[(r n – 1)/(r – 1)] if r ≠ 1 and r > 1 S n = na if r = 1 S n = a[(r n – 1)/(r – 1)] if r ≠ 1 and r > 1 Harmonic progression