##########
# Find the roots of a nonlinear
# equation using the bisection method
##########

# Set the function to be used in f(x)=0.

f:= x-> x^5-3*x^4+2*x^2-4:

# Plot f(x)

# plotsetup(x11);
# plot(f(x),x=-1..3);

# Choose initial interval [a,b]

a:= 2.:  b:=3.:

eps:=1.0;
x1:=a:  x2:=b:
for i from 1 while eps > 0.01 do
	x3:= (x1+x2)/2.;
	if (f(x3)*f(x1)<0.) then
		x2:=x3
	else
		x1:=x3
	end if;
	eps:= abs(f(x3));
end do;