Expansion Techniques | MCQs

Explanation

The Fourier series expansion of an even, periodic function contains only cosine terms and a constant term.

In other words, the sine terms are absent.

Even functions:

An even function is symmetric about the y-axis, meaning f(x) = f(-x). 

Fourier series:

A Fourier series represents a periodic function as a sum of sine and cosine waves. 

Explanation

• The given equation (x + 2)^2 = x^2 + 4x + 4 is an identity because it is true for all values of x.
• An identity is an equation that is always true, and this equation is simply the result of expanding the left-hand side using the binomial theorem.