如何在scilab中绘制函数

Question

我在这里有两个功能：

function y=f(x)
    y=(x*%e^x)-cos(x);
endfunction

function c=regulafalsi(f, x0, x1, tol)
    i=1;
    n(1)=100;
    if f(x0)*f(x1) < 0
        a(1)=x0;
        b(1)=x1;
        c(1)=a(1)-f(a(1))*(b(1)-a(1))/(f(b(1))-f(a(1)));
        printf('i.\t\t a\t\t c\t\t b\t\t f(c)\t  Galat  \n');
        printf('%2d \t %11.4f \t %11.4f \t %11.4f \t %11.4f \n',i,a(i),c(i),b(i),f(c(i)));
        while abs(n(i))>=tol,
            if f(a(i))*f(c(i))< 0
                a(i+1)=a(i);
                b(i+1)=c(i);
            end
            if f(a(i))*f(c(i))> 0
                a(i+1)=c(i);
                b(i+1)=b(i);
            end      
            c(i+1)=a(i+1)-f(a(i+1))*(b(i+1)-a(i+1))/(f(b(i+1))-f(a(i+1)));
            n(i+1)=abs((c(i+1)-c(i))/(c(i+1)));
            printf('%2d \t %11.4f \t %11.4f \t %11.4f \t %11.4f \t %7.4f \n',i+1,a(i+1),c(i+1),b(i+1),f(c(i+1)),n(i+1));
            i=i+1;
        end
    else
        printf(' ');
    end
endfunction

如何绘制这些功能？ 我试过情节（y，c）不工作。