User Manual

f
′ x()
fx ε+()fx ε–()–
2ε
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Chapter 2: Math, Angle, and Test Operations 41
MathPrint™:
Classic: nDeriv(expression,variable,value[,H])
nDeriv(
uses the symmetric difference quotient method, which approximates the numerical
derivative value as the slope of the secant line through these points.
As H becomes smaller, the approximation usually becomes more accurate. In MathPrint™ mode,
the default H is 1
EM3. You can switch to Classic mode to change H for investigations.
You can use
nDeriv( once in expression. Because of the method used to calculate nDeriv(, the TI-84
Plus can return a false derivative value at a nondifferentiable point.
fnInt(
fnInt( (function integral) returns the numerical integral (Gauss-Kronrod method) of expression with
respect to
variable, given lower limit, upper limit, and a tolerance (if not specified, the default is 1âL5).
fnInt( is valid only for real numbers.
In MathPrint™ mode, the default H is 1EM3. You can switch to Classic mode to change H for
investigations.
MathPrint™
Classic
MathPrint™:
Classic: fnInt(expression,variable,lower,upper[,tolerance])