1. function y=f(x)
y=4*cos(x)-exp(x);
endfunction
function x = secante(x0,x1,tol)
j=2;
i=1;
x(1)=x0;
x(2)=x1;
ea(i)=100;
while abs(ea(i))>=tol
x(j+1)=(x(j-1)*f(x(j))-x(j)*f(x(j-1)))/(f(x(j))-f(x(j-1)));
ea(i+1)=abs((x(j+1)-x(j))/x(j+1));
j=j+1;
i=i+1;
end
printf(' i tt x(i) t Error aprox (i) n');
printf('%2d t %11.7f t n',0,x(1));
for k=2:j;
printf('%2d t %11.7f t %7.3f n',k-1,x(k),ea(k-1));
end
endfunction