Sharp EL-5250, EL-5230 operation manual Differential/Integral Functions, Differential function

Chapter 3: Scientific Calculations

Differential/Integral Functions

Differential and integral calculations can only be performed in the NORMAL mode. It is possible to reuse the same equation over and over again and to recalculate by only changing the values without having to re-enter the equation.

•Performing a calculation will clear the value in the X memory.

•You can use both global and local variables in the equation.

•The answer calculated will be stored in the last answer memory.

•The answer calculated may include a margin of error, or an error may occur. In such a case, recalculate after changing the minute interval (dx) or subinterval (n).

•Since differential and integral calculations are performed based on the following equations, in certain rare cases correct results may not be obtained, such as when performing special calculations that contain discontinuous points.

Integral calculation (Simpson’s rule):

1

S=—h{f(a)+4{f (a+h)+f (a+3h)+······+ f (a+(N–1)h)} 3

+2{f (a+2h)+f (a+4h)+······+f (a+(N–2)h)}+f(b)}

b – a

h=——NN=2n a ≤x ≤ b

Differential calculation:

dx	dx
f(x+ ––)–f(x – ––)
2	2

f’(x) =————————

dx

Differential function

The differential function is used as follows.

1.Press b0to enter the NORMAL mode.

2.Input a formula with an x variable.

3.Press @3.

4.Input the x value and press e.

5.Input the minute interval (dx).

6.Press eto calculate.

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