v=5; t=3; L=5; g=9.81;
hl=0.01;  %initial value
hu=10;  %initial value
tolerance=0.0001;
error=1;hrold=1;  %for loop initiation
steps=0; %for loop counting

while (error > tolerance)
steps=steps+1;
hr= (hu+hl)/2;
error=abs((hr-hrold)/hr)*100;
hrold=hr;
fhl=v/sqrt(2*g*hl) - tanh(t*sqrt(2*g*hl)/(2*L));
fhr=v/sqrt(2*g*hr) - tanh(t*sqrt(2*g*hr)/(2*L));
	if (fhr*fhl<0)
		hu=hr;
	else
		hl=hr;
	end
end
root=hr
error
steps