empty sym error, how to solve

syms P1 P2 V1 V2 z1 z2 g p debi Wpump Wturb Eloss Wpumpshaft npump nturb alfa1 alfa2
g=9.807
p=1000
V1=0      
z1=0
alfa1=1;

P2=0 
V2=1       
z2=0    
alfa2=1;

debi=70  %kg/sn
Wpumpshaft=20100
npump=0.683074626865671
Wpump=Wpumpshaft*npump
Wturb=0;
nturb=1
Eloss=0;
ar=((P1/p+V1^2/(2)*alfa1+z1*g)*debi+Wpump==(P2/p+V2^2/(2)*alfa2+z2*g)*debi+Wturb*nturb+Eloss);
vpa(solve(ar,P1),8)  

when i try to solve this it give error. it is ridiculuous. Where is the error.

[Adam Danz]

When I run this, I do not get an error.

Answer 1

[Alan Stevens]

You could use fzero:

P10 = -100;
P1 = fzero(@fn, P10);

function F = fn(P1)

    g=9.807;
    p=1000;
    V1=0;   
    z1=0;
    alfa1=1;

    P2=0; 
    V2=1;      
    z2=0;   
    alfa2=1;

    debi=70;  %kg/sn
    Wpumpshaft=20100;
    npump=0.683074626865671;
    Wpump=Wpumpshaft*npump;
    Wturb=0;
    nturb=1;
    Eloss=0;


    F = ((P1/p+V1^2/(2)*alfa1+z1*g)*debi+Wpump ...
        - (P2/p+V2^2/(2)*alfa2+z2*g)*debi+Wturb*nturb+Eloss);
 
end