Step 1 :The function \((f+g)(x)\) is simply the sum of the two functions \(f(x)\) and \(g(x)\). To find the formula for \((f+g)(x)\), we just need to add the two functions together.
Step 2 :The domain of a function is the set of all possible input values (x-values) which will output real numbers. For the function \((f+g)(x)\), we need to consider the domains of both \(f(x)\) and \(g(x)\). The domain of \(f(x)\) is all real numbers, because any real number can be cubed and subtracted by 1. The domain of \(g(x)\) is all non-negative real numbers, because the cube root of a negative number is not a real number. Therefore, the domain of \((f+g)(x)\) is all non-negative real numbers.
Step 3 :Final Answer: The formula for \((f+g)(x)\) is \(\boxed{(f+g)(x)=x^{3}-1+x^{1/3}}\) and the domain for \((f+g)(x)\) is \(\boxed{[0, \infty)}\)