For questions about recurrence relations, convergence tests, and identifying sequences.

learn more… | top users | synonyms (5)

16
votes
14answers
648 views
+100

New Idea to prove $1+2x+3x^2+\cdots=(1-x)^{-2}$

If $|x|<1 $ prove that $\\1+2x+3x^2+4x^3+5x^4+...=\frac{1}{(1-x)^2}$ 1st proof:suppose ...
-2
votes
0answers
74 views
+100

What are some tricks to solve Progressions quickly?

Recently while solving few questions related to Progressions(specifically, A.P.), I realized one thing that in question like, "Find the sum of following series" and suppose the terms are up to ...