Unit 2.5 Non linear curve fitting y = a * e ^(b*x)

c// algo y = a * e ^(b*x)

start
Read number of data(n)
for i=1 to n:
    1. read xi and yi
    2. Next I
Initializ
    1. sumx=0
    2. sumx2 = 0
    3. sumy = 0
    4. sum xy =0

calculate required sum
for i =1 to n:
    1. sumx= sumx + (xi)
    2. sumx2 = sumx2 + (xi)*(xi)
    3. sumy = sumy + log(yi)
    4. sumxy =sumxy + (xi) * log(yi)

Next i
calculate required constant A and B of Y = A + Bx
A = (sumx * sumy - n*sumxy)/(sumx*sumx - n*sumx2)
B = (sumy - n*A)/sumx

a = pow(10,A)
b = B/log10(e)
display the value of and b
stop


// program
#include <stdio.h>
#include<math.h>
#define e 2.718
int main()
{
    int n;
    float a,x[10],y[10],sumx=0,sumy=0,sumx2=0,sumxy=0;
    printf("Enter the value of n\n");
    scanf("%d",&n);
    printf("Enter the value of x and y\n");
    for(int i=1 ; i<=n ; i++){
        scanf("%f",&x[i]);
    }
    for(int i=1 ; i<=n ; i++){
        scanf("%f",&y[i]);
    }
    for(int i=1 ; i<=n ; i++){
        sumx = sumx + x[i];
        sumx2 = sumx2 + ((x[i])*(x[i]));
        sumy = sumy + log(y[i]);
        sumxy = sumxy + ((x[i]) * log(y[i]));
    }

    float A = ((sumx * sumy) - (n*sumxy))/((sumx*sumx) - (n*sumx2));
    float B =  (sumy - (n*A))/sumx;

    a = pow(10,A);
    float b = B/log10(e);
    printf("\n y= %.2fx + %.2f",a,b);
    return 0;
}


/*
Output
Enter the value of n
5
Enter the value of x and y
1
5
7
9
12
10
15
12
15
21

 y= 1.15x + 0.88
*/