Hi,
You can use the Symbolic Math toolbox to solve your issue as follows:
syms x;
f = sinh(x^2);
T = taylor(f); %finds the Taylor expansion around 0 till the fifth degree by default, to change order
% you can use 'Order' argument of taylor function
x = 0.5;
val = double(subs(T)); %find value of the Taylor polynomial at 0.5
val1 = sinh(x^2); %real value from the function
error = abs(val - val1); %find error
