CODEWITHSUNDEEP
algorithm
user466534
user466534

Reputation:

Function derivatives

I have some function,

int somefunction( //parameters here, let's say  int x) {
    return something  Let's say x*x+2*x+3 or does not matter
}

How do I find the derivative of this function? If I have 

int f(int x) {
    return sin(x);
}

after derivative it must return cos(x).

Upvotes: 2

Views: 265

Answers (2)

Betamoo
Betamoo

Reputation: 15870

You can get the numerical integral of mostly any function using one of many numerical techniques such as Numerical ordinary Differential Equations

Look at: Another question

But you can get the integration result as a function definition with a library such as Maple, Mathematica, Sage, or SymPy

Upvotes: 1

Andy Mortimer
Andy Mortimer

Reputation: 3707

You can approximate the derivative by looking at the gradient over a small interval. Eg

const double DELTA=0.0001;
double dfbydx(int x) {
  return (f(x+DELTA) - f(x)) / DELTA;
}

Depending on where you're evaluating the function, you might get better results from (f(x+DELTA) - f(x-DELTA)) / 2*DELTA instead.

(I assume 'int' in your question was a typo. If they really are using integers you might have problems with precision this way.)

Upvotes: 3

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