Chapter 10 - The Laplace Transform and Some Elementary Applications - 10.2 The Existence of the Laplace Transform and the Inverse Transform - True-False Review - Page 685: a

True

Let us consider that the function $f$ is periodic function with period $T$ . $f(t+T)=f(t)$ Now, $f(t+2T)=f(t+T+T)=f(t+T)=f(T)$ This implies that $2T$ can be considered a period of function $f$. Therefore, the given statement is $\bf{True}$.