#include <stdio.h>
#include <math.h>

typedef double(*fun)(double x);

double f(double x)
{
return 0.1*pow(x,2)-x*log(x);
}
double g(double x)
{
return tan(x)-(1/3.0)*pow(tan(x),3)+(1/5.0)*pow(tan(x),5)-(1/3.0);
}
double f1(fun f, double x)
{
double h = 0.0000001;
return (f(x+h)-f(x))/h;
}
double f2(fun f, double x)
{
double h = 0.0000001;
return (f(x-h)+f(x+h)-2*f(x))/(h*h);
}
double epsilon()
{
long double x=1;
for (;1+x/2 !=1;x=x/2){}
return x;
}
double dihotomiya(double A, double B, fun f)
{
double eps=epsilon()*100;
double a=A;
double b=B;
while(fabs(a-b) >eps )
{
if( f(a)*f((a+b)/2) > 0 )
a=(a+b)/2;
else
b=(a+b)/2;
}
return (a+b)/2;
}
double interaziya(double A,double B, fun f)
{
double x=(A+B)/2;
double a=A;
int flag=0;
long double eps=epsilon()*1e10;
while(a<=B)
{
if(f1(f,a)<1)
flag=1;
a=a+eps;
}
while(fabs(f(x)) > eps && flag==1)
x=(fabs(f(x))-x);
if(flag==1)
printf("Iteration: %f\n", x);
else
printf("Iteration: Don't exist\n");
}
double newton(double A,double B,fun f)
{
double x=(A+B)/2;
double temp=0;
double a=A;
long double eps=epsilon()*1e10;
int flag=0;

while(a<=B)
{
if(fabs(f(a)*f2(f,a))< pow(f1(f,a),2))
flag=1;
a=a+eps;
}
while(fabs(f(x)) > eps && flag ==1)
x=x-f(x)/f1(f,x);
if(flag==1)
printf("Newton: %f\n", x);
else
printf("Newton: Don't exist\n");
}

int main()
{
long i;
printf("Computer epsilon: %e\n", epsilon());
printf("Variant 20\n");
printf("Dichotomy: %f\n", dihotomiya(1, 2,f));
interaziya(1, 2,f);
newton(1, 2,f);
printf("Variant 21\n");
printf("Dichotomy: %f\n", dihotomiya(0, 0.8, g));
interaziya(0, 0.8, g);
newton(0, 0.8, g);
scanf("%d",&i);
return 0;
}