Here's the question you clicked on:
pasta
Define what is meant by a real valued fuction?
A real-valued function f is one whose codomain is the set of real numbers or a subset thereof. This includes integers, fractions, irrational numbers, and transcendental numbers Sometime this symbol is used to denote the real numbers. \[\mathbb{R} \] This does not include complex numbers, numbers consisting of a real and imaginary part. So, \[ y = sin(x), y \in \mathbb{R}\] but, \[y = isin(x), y \in \mathbb{C}\]
put it simply that range of real valued function is only real numbers, and not complex i.e y=x^2+x+1 ....is not a real valued function ,
but this equation gives real numbers always .could you just GIVE A CASE WHERE THE EQUATION DOES NOT GIVE A REAL NUMBER IF I WAS TO SUBSTITUTE FOR ANY VALUE FROM THE NUMBER LINE