The correct answer is C. Cosine and sine terms.
A trigonometric Fourier series is a way of representing a periodic function as a sum of sine and cosine waves. The function can be any periodic function, such as a square wave, a triangle wave, or a sawtooth wave.
The Fourier series is written as a sum of sine and cosine terms, each with its own frequency and amplitude. The frequencies of the terms are multiples of the fundamental frequency of the function. The amplitude of each term is determined by the function’s value at that frequency.
The Fourier series can be used to analyze a periodic function. It can be used to find the frequency components of the function, and to determine the amplitude of each frequency component.
The Fourier series can also be used to synthesize a periodic function. It can be used to create a function that has the same frequency components as the original function.
The Fourier series is a powerful tool for analyzing and synthesizing periodic functions. It is used in many fields, including engineering, physics, and mathematics.
Here is a brief explanation of each option:
- Option A: Cosine terms. This is not correct because the Fourier series can also have sine terms.
- Option B: Sine terms. This is not correct because the Fourier series can also have cosine terms.
- Option C: Cosine and sine terms. This is the correct answer because the Fourier series can have both cosine and sine terms.
- Option D: Dc and cosine terms. This is not correct because the Fourier series does not have dc terms.