How do you find the range from the set of domains?

Answer 1

You need to have some idea about the behavior of whatever function you are using. As an example, if your function is f(x) = x2, you probably know that the lowest value this can have is 0 (for x = 0), and that for other values of x, the function will be positive. Also, that the function can achieve any positive value. So, in summary, for the set of real numbers, the function can take on any value greater or equal to zero. As another example, the sine function can only produce values between -1 and 1 (inclusive).