Compare $E_{x1}$ and $E_{x2},$ the values of the $x-$component of the electric field at $t=0.E_{x1}$ is evaluated at $(x=0,y=0,z=z_{\text{m}\text{a}\text{x}}),$ while $E_{x2}$ is evaluated at $(x=($:$nm,y=nm,z=z_{\text{m}\text{a}\text{x}}\}.$

$E_{x1}=E_{x2}{E}_{x1}>E_{x2}{E}_{x1}$

$E_{x1}=E_{x2}$

$E_{x1}>E_{x2}$