how to call derivative ?

[jabka]

Hello ,...

in my last work i need to use Maclaurin serie to calculate stuff (in calculs hws).
but to do that i need to some home find Derivative.

how can i call a func to use derivatives?

i read math.h and didn't find any mention for this (nor did apropos revealed some thing close to it).

[zacs7]

Well, as far as I know you'd have to parse the equation and differentiate it via 2nd principles.
math.h doesn't contain anything for parsing math equations, you'll need a parser for that.

Write your own or use a 3rd party one?

[Happy_Reaper]

i read math.h and didn't find any mention for this (nor did apropos revealed some thing close to it).

There isn't anything to do derivatives in there. You have to approximate it or use some 3rd party libraries.

[zacs7]

As Happy_Reaper said, you could consider Derivative Approximation (http://www.geometrictools.com/Docume...ifferences.pdf)

[jabka]

and i thout that my life would be easy .. (i thouth that there is a way just to call some func to use dervetive):

weal it time to code .. XD ..

[Happy_Reaper]

and i thout that my life would be easy ..

It isn't that difficult. First and second derivative approximations are just a formula that you can find here. I don't think that you need the higher-order ones (but that's depending on your precision threshold).

[brewbuck]

Why not just use the definition of derivative to approximate it?

double approx_deriv(double (*f)(double), x)
{
    double h = 1e-12; /* Very small */
    return (f(x + h) - f(x)) / h;
}