Shortcut Methods

**Infinite Series Tricks and Shortcuts: JEE & CBSE Solutions **

1. Infinite Geometric Series Sum:

Formula: S=a1r where ‘a’ is the first term , ‘r’ is common ratio , ‘S’ denotes the sum

##2. Ratio Test (Convergence/Divergence): If limn|an+1an|=L

  • Converges if L<1 *Diverges if L>1

*Ambiguous (inconclusive) when L=1 > >

3. Alternating Series Approximation Error:

Errorbn+1

where n is an index large enough, and ({ b_{n+1} }) is the succeeding term after the final considered term .

These methods significantly simplify complex sums, enable effective convergence, divergence analysis, and provide accurate numeric estimations for JEE and CBSE examinations!