Shortcut Methods

Shortcuts and Tricks for JEE/CBSE Numericals

Arithmetic Progressions (AP)

  1. If a and b are the first and last terms, and n the number of terms in an AP, then the sum of the terms, Sn, is given by: Sn=n2(a+b)

  2. The n-th term, Tn, of an AP with first term a and common difference d is given by: Tn=a+(n1)d

Geometric Progressions (GP)

  1. The sum of the first n terms of a GP with first term a and common ratio r is given by: Sn=a(1rn)1r,r1

  2. The n-th term, Tn, of a GP with first term a and common ratio r is given by: Tn=arn1

Harmonic Progressions (HP)

  1. The sum of the first n terms of a HP with first term a and common difference d is given by: Sn=n2a[1+(n1)d]

  2. The n-th term, Tn, of a HP with first term a and common difference d is given by: Tn=an