## taudiff

Tau derivative evaluation.

Tau derivative evaluation.

[v, f] = taudiff(step, x, fun, order)

Evaluates the derivative from an approximated function.

step = evaluation step (double). x = independent tau variable (itau object). fun = function f(x) (char or double vector). order = derivative order (integer).

v = v(x). f = coefficients for the approximation diff('fun(x)', order).

x = itau('LegendreP', [0 1], 5); [v, f] = taudiff(0.1, x, ''x^2-3*x+1'', 2); or: x = itau('LegendreP', [0 1], 5); [v, f] = taudiff(0.1, x, [-1/6 -1 1/6]', 2); In the first example the function is interpolated by orthogonal basis whereas in the second the coefficients are already provided.

taufred, tauint, taudiff.