What is the mathematical signature distinguishing a standing wave $y(x, t)$ in a one-dimensional system?

Answer

The spatial dependence is independent of the time dependence

In the mathematical description of a standing wave, the spatial term (governing the shape or maximum possible oscillation) is separated and independent of the time term (governing how that maximum oscillation occurs over time).

What is the mathematical signature distinguishing a standing wave $y(x, t)$ in a one-dimensional system?
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