My code is about finding head value using bisection or false error method .But its showing parse error for xl=input("the lower value");i don't know how to solve it...

%define function of head

function h = formula(n)

%Input the value of v,g,H,L,t

v=5;

g=9.81;

L=4;

t=2.5;

s=sqrt(2*g*n);

h = v -( s*tanh((t*s)/2*L));

end

%Input the value of lower and upper limit

xl=input("The lower value xl=");

xu=input("The upper value xu=");

es=0.01;

xold=0.00;

if formula(xl)*formula(xu)>0

fprintf("The value of H can not be calculated");

else

d=input("For the value of head by bisection method press 1 and for false position method press 2 for d,so d= ");

if d==1

xr=(xl+xu)/2;

else

xr=(((xu*formula(xl))-(xl*formula(xu))) /(formula(xl)-formula(xu))) ;

end

if (d==1&&d==2)

for i=1:100

if formula(xl)*formula(xr)<0

xu=xr;

elseif formula(xl)*formula(xr)>0

xl=xr;

else

break;

end

end

if abs((xr-xold)/xr)<=es

end

xold=xr;

end

fprintf("Value of head in this method is %f",xr);

end

Answer 1

[KSSV]

You have to either copy the function below the main code or copy the function into a different mfile and then run the main code.

Try running the below code.

%Input the value of lower and upper limit
xl=input("The lower value xl=");
xu=input("The upper value xu=");
es=0.01;
xold=0.00;
if formula(xl)*formula(xu)>0
    fprintf("The value of H can not be calculated");
else
    d=input("For the value of head by bisection method press 1 and for false position method press 2 for d,so d= ");
    if d==1
        xr=(xl+xu)/2;
    else
        xr=(((xu*formula(xl))-(xl*formula(xu))) /(formula(xl)-formula(xu))) ;
    end
    if (d==1&&d==2)
        for i=1:100
            
            if formula(xl)*formula(xr)<0
                xu=xr;
            elseif formula(xl)*formula(xr)>0
                xl=xr;
            else
                break;
            end
        end
        if abs((xr-xold)/xr)<=es
            
        end
        xold=xr;
    end
    fprintf("Value of head in this method is %f\n",xr);
end

%define function of head
function h = formula(n)
%Input the value of v,g,H,L,t
v=5;
g=9.81;
L=4;
t=2.5;
s=sqrt(2*g*n);
h = v -( s*tanh((t*s)/2*L));
end

[Atia Ashrafy]

Thank you very much!!!!! it worked...

[KSSV]

Thanks is accepting/ voting the answer.