Real Function
A function whose range is in the real numbers is said to be a real function, also called a real-valued function.
See also
Complex Function, Function, Real Variable, Scalar Function, Vector FunctionExplore with Wolfram|Alpha
WolframAlpha
More things to try:
Cite this as:
Weisstein, Eric W. "Real Function." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/RealFunction.html