let x $1($t$)$ be a continuous$-$time periodic signal with fundamental frequency $1$ and Fourier coefficients ak$.$ Given

that x $2($t$)=$ x$1($t $-1)+$ x$1(1-$ t$),$ determine a relationship between the Fourier coefficients b k of x$2($t$)$ and ak$.$ Also,

determine the relationship between the fundamental frequency $2$ of x$2($t$)$ and $1.$