GP: sum of first n terms (S_n = a(1-r^n)/(1-r), r≠1; S_n = n a if r=1)
jee-mainjee-advanced
S_n = a(1-r^n)/(1-r), r≠1; S_n = n a if r=1
What each symbol means
| Symbol | What it stands for |
|---|---|
| a | First term |
| n | Number of terms |
| r | Common ratio |
| S_n | Sum first n terms |
When to use this
r=1 is separate linear case.