Problem while solving the problem ode45

function dy=pair(t,y,a,b,c)
dy(1)= -a.*y(1)+b*exp(-t);
dy(2)=(-y(1).*y(2).^2)/c;
end
>> tspan=0:0.1:0.4;
>> a=2;
>> b=4;
>> c=3;
>> [t,y]=ode45(@pair,tspan,[2 4]);
ERROR
Error using pair (line 2)
Not enough input arguments.

Error in odearguments (line 87)
f0 = feval(ode,t0,y0,args{:});   % ODE15I sets args{1} to yp0.

Error in ode45 (line 113)
[neq, tspan, ntspan, next, t0, tfinal, tdir, y0, f0, odeArgs, odeFcn, ...

I suspect I know a bit of what's going wrong, yet I'm at a loss for how to fix it. Any help is much appreciated!

[madhan ravi]

upload pair function , ah didn't notice ,it was at the beginning XD

Answer 1

[Torsten]

[t,y]=ode45(@(t,y)pair(t,y,a,b,c),tspan,[2 4]);

function dy=pair(t,y,a,b,c)
dy(1)= -a.*y(1)+b*exp(-t);
dy(2)=(-y(1).*y(2).^2)/c;
dy = dy.'
end

[ruban ramalingam]

Thank you sir... Its working..

Can you explain dy=dy'?

[Star Strider]

ODE functions must return a column vector output. That assignment does a simple transpose operation to create ‘dy’ as a column vector.

[ruban ramalingam]

Thank you sir