Casio fx-991ES Calculator User Manual


 
E-37
k Σ Calculations
With Σ(, you can obtain the sum of an input f(x) expression for a
specific range. Σ calculations are performed using the following
formula.
Σ( f(x), a, b) = f(a) + f(a + 1) + .... + f(b)
f(x): Function of X (All non-X variables are treated as
constants.)
a:Calculation range start point
b:Calculation range end point
a and b are integers in the range of –1 × 10
10
< a < b <
1 × 10
10
.
• The calculation step is fixed at 1.
(, d/dx(, Pol(, Rec(, and Σ( cannot be used within f(x), a, or b.
•Pressing A will interrupt an ongoing Σ calculation.
Appendix <#035> Σ (X + 1, 1, 5) = 20
k Rectangular-Polar Coordinate Conversion
Rectangular Polar Coordinates
Coordinates (Rec) (Pol)
Coordinate conversion can be performed in the COMP, STAT,
MATRIX, and VECTOR calculation modes.
Converting to Polar Coordinates (Pol)
Pol(X, Y) X: Specifies the rectangular coordinate X value
Y: Specifies the rectangular coordinate Y value
•Calculation result
θ
is displayed in the range of –180° <
θ
< 180°.
•Calculation result
θ
is displayed using the calculator’s default angle
unit.
•Calculation result r is assigned to variable X, while
θ
is assigned
to Y.
Converting to Rectangular Coordinates (Rec)
Rec(r,
θ
) r : Specifies r value of polar coordinate
θ
:Specifies
θ
value of polar coordinate
• Input value
θ
is treated as an angle value, in accordance with the
calculator’s default angle unit setting.
•Calculation result x is assigned to variable X, while y is assigned
to Y.