IF condition for infinity values

For the code below, sometimes the values of 'steadystate' == Infinity or NaN. How do I check this condition and display an error message? I have not posted my whole code. Initial guess councoutGuess=[0.1;0.1;0.1;0.1] initial steadystate values = [ 0.1504734, -0.049281077, 0.14977213, 0.34987724]

while abs(steadystate-concoutGuess)>Error %Convergence error criteria for the Newton Rhapson loop
bigmatrix=alt_bigmatrix; %Using the stored symbolic matrix for the loop calculations
concoutGuess=steadystate; %Updating values
concout=steadystate;
fA= ((flowinA*concinA-flowout*concout(1))/Vol) - k1*concout(1)*concout(2); %Recalcualting values similar to previous calculations
fB= ((flowinB*concinB-flowout*concout(2))/Vol) - k1*concout(1)*concout(2) - k2*concout(2)*concout(3);
fC= ((-flowout*concout(3))/Vol) + k1*concout(1)*concout(2) - k2*concout(2)*concout(3);
fD= ((-flowout*concout(4))/Vol) + k1*concout(2)*concout(3);
molflow = [ fA; fB; fC; fD ];
bigmatrix= subs(bigmatrix); %Substituting updated values and calculating in symbolic form
differential=inv(bigmatrix);
differential=vpa(differential,8);%Evaluating symbolic and rounding to specified significant figures
molflow=vpa(molflow,8);
steadystate = concoutGuess - (differential*molflow); %Newton Rhapson formula for steady state
steadystate = vpa(steadystate,8);
fprintf('%15.10g %15.10f %15.10f %15.10f %15.10f\n',count,steadystate(1),steadystate(2),steadystate(3),steadystate(4))
steadyStateMatrix(:, count) = steadystate;% storing iterations as a matirx, steadystate is a column vector
  count = count + 1;

end

Answer 1

[Fangjun Jiang]

isnan()
isfinite()

[Remston Martis]

Thanks!!