How can you make an input to a symbolic variable?

varprompt='Enter Variable (space-separated):';
var=inputdlg(varprompt);
syms(sym(string(var)));

eqprompt='Enter Equation (from highest to lowest degree):';
equation=inputdlg(eqprompt);

k=diff(equation)

I dont know what to do. How do you make the program solve the equation? Im having trouble turning the var input to a symbolic variable so that i can use it to solve the equation.

Answer 1

[madhan ravi]

equation = {'x^2 + x'};
diff(str2sym(equation))

ans = 

2 x+1

equation = {'x^2 + y'};
eq = str2sym(equation);
syms(symvar(eq))
diff(str2sym(equation), x)

ans = 

2 x