TI-83 Plus Math, Angle, and Test Operations 70
nDeriv(
nDeriv( (numerical derivative) returns an approximate derivative of
expression with respect to variable, given the value at which to calculate the
derivative and H (if not specified, the default is 1âL3). nDeriv( is valid only
for real numbers.
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.
εεε
2
)(()(
)(' −−+
=xfxf
xf
As H becomes smaller, the approximation usually becomes more
accurate.
You can use nDeriv( once in expression. Because of the method used to
calculate nDeriv(, the TI-83 Plus can return a false derivative value at a
nondifferentiable point.