MATLAB: How to use fsolve an implicit equation

fsolveimplicitode45

clc, clear
a1=28*7*400;                        %%ft^2
po=40.6;                            %%psi







delpio=9;                           %%psi
qf=1525;                            %%gpm


qo=qf;
pp=16.4;                            %%psi
qp=1234;                            %%gpm
depr1=24.9;                         %%psi
delpr2=18.2;                        %%psi
PH=360;                                     %%ft
lp=2.76*.264/(60)^2*14.5;                   %%gal/m*min^2/psi
k2=1.75*10^-4*60^1.67*14.5/264.172^1.67;     %%psi/(gal/min)^1.67
k3=2.27*10^-2;                      %%(m^3/h)^.6/m^2
g=32.17;                            %%ft/s^2
rhoh20=62.4;                        %%lbs/ft^3
pf=rhoh20*g*PH*1.488*.000145;       %%psi
delpo=pf-po;                     %%psi
icQ=qo;                         %%gpm
icdelp=delpo;                   %%psi
function dydx=odes(jw,a1,k2)
dydx=zeros(2,1);
dydx(1)=-jw*a1;
dydx(2)= -k2*y(1)^1.67;
end 
function F=JW(lp,qo,delpio,k3,y)
F=lp*(y(2)-qo*delpio/y(1)*exp(z/(k3*y(1)^0.40))-z;
 
end 
xo=0;
X=@JW
jw=fsolve(JW,xo);
xspan=[0 50];
[x,y]=ode45(@odes,xspan,[icQ icdelp]);
Error in fsolve (line 242)
            fuser = feval(funfcn{3},x,varargin{:});
Error in mhlro (line 24)
jw=fsolve(@(z)JW(lp,qo,delpio,k3,y),xo);
Caused by:
    Failure in initial objective function evaluation.
    FSOLVE cannot continue.
FIrst is my function of differntial equations
followed by my function that i want to fsolve.
I want to find the number z in the equation but that equation is dependent on the differential equations and the differentials are depenedent on z.
The error i get is below.

Best Answer

function F=JW(lp,qo,delpio,k3,y,z)                          %<- z is an INPUT
  F=lp*(y(2)-qo*delpio/y(1)*exp(z/(k3*y(1)^0.40)))-z;
end
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