function[n]  =  Lab5_1( f,X0,A,n0,e )
% f - функция с символьными х,у
% Х0 - координаты начальной точки
% А - отрезок [a,b]
% n0 - начальное число отрезкой разбиения
% е - точность


% Starting Point
x0=X0(1);
y0=X0(2);

% Interval
a=A(1);
b=A(2);


dx=(b-a)/n0;

% X and Y arrays for plot
X(1)=x0;
Y(1)=y0;

% X1 and Y1 arrays for n*2 plot
X1(1) = x0;
Y1(1) = y0;

for i=1:1:n0
syms x y;
if (Y(i) + subs(f,{'x','y'},[X(i) Y(i)])*dx == inf)
    break
else
    Y(i+1) = Y(i) + subs(f,{'x','y'},[X(i) Y(i)])*dx;
end
X(i+1) = X(i) + dx;
end
plot(X, Y, 'r')
dx = dx/2;
n = n0*2;
for i=1:1:2*n0
if (Y1(i) + subs(f,{'x','y'},[X1(i) Y1(i)])*dx == inf)
    break
else
    Y1(i+1) = Y1(i) + subs(f,{'x','y'},[X1(i) Y1(i)])*dx;
end
X1(i+1) = X1(i) + dx;
plot(X1,Y1,'g');
end
end