Displaystylesum_ n14 dfrac k n1 n14. Essentially y is replaced with f x. In f x the f is the name used to identify the given function while the x is the argument of the function and describes the input value of the function.
Found in mathematical writing.
In the history of mathematics these symbols have denoted numbers shapes patterns and changeThe notation can also include symbols for parts of the conventional discourse between. Thats simple I hope you learned the best way to write the mathematical expressions. Then an odd integer being one more than a multiple of 2 is x 2 m 1. Equivalent expressions are x is a member of A x belongs to A x is in A and x lies in A.