# Translations:D’Alembert’s solution/6/en

is the general solution of the 1D wave equation, where and are arbitrary functions. This solution is known as the d’Alembert formula. The letter *f* is the standard notation for a mathematical function, and this usage will always be so. However, we already have used the letter *f* for the frequency, and that can lead to confusion. An alternative would be to denote frequency by the Greek letter *v* (lowercase nu), which is done in Sheriff’s *Encyclopedic Dictionary of Applied Geophysics* (Sheriff, 2002^{[1]}). However, the Greek nu looks too much like the letter *v*, which is used for velocity. Because the meaning should be clear from the context, in this book we will use the letter *f* both as a symbol for a mathematical function and as a symbol to denote frequency. A rose is a rose is a rose. In other words, things are what they are.

- ↑ Sheriff, R. E., 2002, Encyclopedic dictionary of applied geophysics, 4th ed: SEG Geophysical Reference Series No. 13.