How To Find The Roots Of A Cubic Function

Observe cubic root of a number in C++

Hither we volition see how to get the cubic root of a number. Suppose a number is say 27, then the cubic root of this number is 3. To solve this problem, we will ascertain our own logic without using some library functions. We will use the binary search approach. We have to follow these steps to solve this trouble.

Suppose we have threshold value like threshold = 0.000001

Start the left value as 0, and right value as number
calculate mid := (left + correct)/ii
if the absolute value of (number – mid3) is less than threshold, and so return mid as reply
if mid3 is greater than number, then set correct := mid
if mid3 is less than number, then set left := mid

Example

#include<iostream> #include<cmath> using namespace std;    double cubeRoot(int num) {    double threshold = 0.000001;    double left = 0, right = num;    double mid;    while(left <= right){       mid = (left + right)/ii;       if(abs(num - (mid*mid*mid)) < threshold)          return mid;       if((mid*mid*mid) > num)          right = mid;       if((mid*mid*mid) < num)          left = mid;    } } int main() {    int n = three;    cout << "cube root of 3 is: " << cubeRoot(n); }