For example, a series of any periodic signals can be decomposed into a series of sinusoidal signals, the frequency of which is an integer multiple of the fundamental frequency.

Trigonometric function, any periodic signal can be synthesized by a series of sinusoidal signals.

Function, there is a functional relationship between the excitation and response of any system.

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Specialized mathematics courses during college include: advanced mathematics, probability theory, engineering mathematics (complex variable function, linear algebra, field theory, digital calculation).

Electromagnetic field theory requires good knowledge of calculus.

In a word, mathematics is the basis of any physical analysis, universities will have more advanced mathematical knowledge, and middle schools are the foundation.