TI-Nspire CX II field manual for IB Math
10
All coursesSumming a sequence
Use the calculator's Σ command to add the terms of a sequence over a specified range.
Find n=1∑123(1.2)n−1.
1
From the Scratchpad calculator, press → 4: Calculus → 3: Sum to insert the Σ template, with boxes for the index, limits, and summand.
2
Fill the template, moving between boxes with : type for the index, for the lower limit, and for the upper limit. Type the summand with .
3
Press to evaluate.
n=1∑123(1.2)n−1≈119.
Your turn
Work each one on your calculator, then check the answer.
- 1
Find n=1∑184(1.15)n−1.
- 2
Find n=1∑105(0.8)n−1.
- 3
Find n=1∑20n(0.8)n.