Texas Instruments TI-84 Plus Silver Edition

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F
FF
Finding a Riemann Sum
inding a Riemann Suminding a Riemann Sum
inding a Riemann Sum
To calculate a Riemann Sum using left endpoints, follow these instructions:
Enter the function at Y= as Y1 .
Enter the number or rectangles (n) as N, so press n, STO>, ALPHA, N .
Enter the left endpoint of the interval (a) as A, so press a, STO>, ALPHA, A.
Compute
x
∆
and store it as W . Press the number, then STO> ALPHA W .
Press Y= and enter the following commands as Y5 : sum(seq(Y1(A + K*W)*W, K, 0, N-1)
Press VARS, Y-VARS, Function, 5, ENTER.
Example: Use a Riemann Sum to approximate the area under
2
1
( ) 3
2
f x x
= +
using 15
rectangles and left endpoints on the interval [1, 6].
Enter
( )
f x
as Y1 on 15 STO> ALPHA N 1 STO> ALPHA A
the Y= menu.
Compute
x
∆
. ANS STO> W 2
nd
STAT (choose MATH ).
Go to Y= and arrow down to Y5 .
Result. Choose sum(. Result. Press 2
nd
STAT and Result. Press seq( .
choose OPS.