Casio fx-CG50 field manual for IB Math
9
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 MAIN MENU open Run-Matrix (icon 1). Check Input/Output is set to Math under (SET UP), then insert the summation template: press (MATH), then (▶) for the second strip, then (Σ().
2
The cursor starts in the summand box, so type the expression first: . Then move between the remaining boxes with the arrow keys: the index n with , for the lower limit, and for the upper limit.
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.