I've been working on numerical methods to solve polynomial and non-polynomial equations. I wanted to use numderivative to calculate the defined derivative of a function entered by the user with the following simple code:
clc
clear
x0 =input('Enter the x value: ') // x0 = 4
function y = f(x)
y = input('Enter your function: ') // y = sqrt(x)
endfunction
dd = numderivative(f,x0)
printf('The definite derivative value of f(x) in x = %d is %.6f',x0,dd)
The output is the following:
Enter the x value: 4
Enter your function: sqrt(x)
Enter your function: sqrt(x)
The definite derivative value of f(x) in x = 4 is 0.250000
This code asks for the function twice. I would like to know how to solve that problem. Thank in advance.
No it is not possible to enter a function, but you can enter the instructions of the function:
x0 =input('Enter the x value: ') // x0 = 4
instr = input('Enter the expression to derivate as a function of x: ',"s")//sqrt(x)
deff("y=f(x)","y="+instr)
dd = numderivative(f,x0)
printf('The definite derivative value of f(x) in x = %d is %.6f',x0,dd)