Can anyone please help me to understand the below mentioned code?

function [pwav]=p_wav(x,a_pwav,d_pwav,t_pwav,li)

l=li;

a=a_pwav;

x=x+t_pwav;

b=(2*l)/d_pwav;

n=100;

p1=1/l;

p2=0;

for i = 1:n

      harm1=(((sin((pi/(2*b))*(b-(2*i))))/(b-(2*i))+(sin((pi/(2*b))*(b+(2*i))))/(b+(2*i)))*(2/pi))*cos((i*pi*x)/l); 

      p2=p2+harm1;

end
pwav1=p1+p2;

pwav=a*pwav1;

function [qwav]=q_wav(x,a_qwav,d_qwav,t_qwav,li)

l=li;

x=x+t_qwav;

a=a_qwav;

b=(2*l)/d_qwav;

n=100;

q1=(a/(2*b))*(2-b);

q2=0;

for i = 1:n

      harm5=(((2*b*a)/(i*i*pi*pi))*(1-cos((i*pi)/b)))*cos((i*pi*x)/l);

      q2=q2+harm5;

end

qwav=-1*(q1+q2);

function [swav]=s_wav(x,a_swav,d_swav,t_swav,li)

l=li;

x=x-t_swav;

a=a_swav;

b=(2*l)/d_swav;

n=100;

s1=(a/(2*b))*(2-b);

s2=0;

for i = 1:n

      harm3=(((2*b*a)/(i*i*pi*pi))*(1-cos((i*pi)/b)))*cos((i*pi*x)/l);

      s2=s2+harm3;

end

swav=-1*(s1+s2);

function [twav]=t_wav(x,a_twav,d_twav,t_twav,li)

l=li;

a=a_twav;

x=x-t_twav-0.045;

b=(2*l)/d_twav;

n=100;

t1=1/l;

t2=0;

for i = 1:n

      harm2=(((sin((pi/(2*b))*(b-(2*i))))/(b-(2*i))+(sin((pi/(2*b))*(b+(2*i))))/(b+(2*i)))*(2/pi))*cos((i*pi*x)/l);      

      t2=t2+harm2;
  end
  twav1=t1+t2;

twav=a*twav1;

function [uwav]=u_wav(x,a_uwav,d_uwav,t_uwav,li)

l=li;

a=a_uwav

x=x-t_uwav;

b=(2*l)/d_uwav;

n=100;

u1=1/l

u2=0

for i = 1:n

      harm4=(((sin((pi/(2*b))*(b-(2*i))))/(b-(2*i))+(sin((pi/(2*b))*(b+(2*i))))/(b+(2*i)))*(2/pi))*cos((i*pi*x)/l);

      u2=u2+harm4;
  end

uwav1=u1+u2;

uwav=a*uwav1;