#include <iostream>

double pow (double a,double b) {
    double p = 1;
    if (b==0) return 1;
    for (int i = 0;i<b;i++) {
        p*=a;
    }
    return p;
}

double fact (int n) {
    if (n==0) return 1;
    int p = 1;
    for (int i = 1;i<=n;i++ ){
        p*=i;
    }
    return p;
}

double functio1 (double x,double e) {
    double sum = 0;
    double p = 1;
    int i = 1;
    while (p>=e) {
        p = pow(-1,i) * pow(x,(2*i-1)) / pow(2.718281828459045235360287471352662497757247093699959574966,i) / fact(i);
        sum+=p;
        i++;
    }
    return sum;
}