Matlab help in incremental methods

Does this code look correct for following problem? I was told there was an issue in it, teacher told me to find it rather than show me.

clc;
clear all;
%%Incremental Method
g = 9.81;
v = 5;
t = 3;
L = 5;
h = 0; %initial guess of height
dh = 0.01;   %incremental value
f1 = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));   %initial error
h = h+dh;
f2 = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
while f1*f2 > 0        % check whether solution exists or not
    f1 = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
    h = h+dh;
    f2 = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
end
disp(h);   % result height using incremental method
%%Bisection Method
g = 9.81;     
v = 5;        % 2nd question part a
t = 3;
L = 5;
syms h
f(h) = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
a = 0 ;    %inital guesses of height
b = 5;     %inital guesses of height
if f(a)*f(b)>0
    disp('Wrong choice')
else
    p = (a + b)/2;     %bisection algorithm
    err = abs(f(p));
    while err > 1e-3
   if f(a)*f(p)<0
       b = p;
   else
       a = p;        
   end
    p = (a + b)/2;
   err = abs(f(p));
    end
end
disp(a) % result height using bisection method

v = 5;        % 2nd question part b
t = 3;
L = 10;
syms h
f(h) = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
a = 0 ;    %inital guesses of height
b = 5;     %inital guesses of height
if f(a)*f(b)>0
    disp('Wrong choice')
else
    p = (a + b)/2;    %bisection algorithm
    err = abs(f(p));
    while err > 1e-3
   if f(a)*f(p)<0
       b = p;
   else
       a = p;        
   end
    p = (a + b)/2;
   err = abs(f(p));
    end
end
disp(a) % result height using bisection method

v = 10;        % 2nd question part c
t = 2;
L = 10;
syms h
f(h) = v - sqrt(2.*g.*h)*tanh((t./(2*L))*sqrt(2.*g.*h));
a = 0 ;     %inital guesses of height
b = 10;     %inital guesses of height
if f(a)*f(b)>0
    disp('Wrong choice')
else
    p = (a + b)/2;     %bisection algorithm
    err = abs(f(p));
    while err > 1e-3
   if f(a)*f(p)<0
       b = p;
   else
       a = p;        
   end
    p = (a + b)/2;
   err = abs(f(p));
    end
end
disp(a) % result height using bisection method

Results

    1.4900 m

    1.4844 m

    2.2192 m

    7.3340 m