sum of the terms of a geometric sequence
- Let (`u_(n)`) be a geometric sequence of common ratio -3, and of first term `u_(0)= -1 `. Let S be the sum of `u_(4)` to `u_(12)`. S=`u_(4)`+`u_(5)`+`u_(6)`+`. . .`+`u_(12)`.
- Calculate `u_(4)`
- Calculate `u_(12)`.
- Deduce S.
Course reminder : Numerical sequences