Matlab help, code want run eval command

Calculate and plot the total response of the spring$$mass$$damper system with m $=100$ kg$,\backslash$zeta $=0\mathrm{.}1,$ and k $=1000$ N$>$m to the signal defined by

with maximum force of $1$ N$.$ Assume that the initial conditions are zero, and let T $=2\backslash$pi s$.$

$F(t)=\{\begin{array}{cc}\frac{4}{T}t-1,& 0t\frac{T}{2}\\ 1-\frac{4}{T}(t-\frac{T}{2}),& \frac{T}{2}tT\end{array}$

Here is my code:

clc$,$clear,close all;

m $=100$;

c $=63\mathrm{.}25$;

k $=1000$;

T $=2*$pi;

syms s t

expr$1=($exp$(-$s$*$t$)*(($t$/$T$)-1))$;

expr$2=($exp$(-$s$*$t$)*((1-(1/$T$)*($t$-($T$/2)))))$;

F $=(4/(1-$exp$(-2*$pi$*$s$)))*($int$($expr$1,$t$,0,$pi$)+($int$($expr$2,$t$,$pi$,2*$pi$)))$;

X $=$ F$/($m$*$s$^2+$c$*$s$+$k$)$;

x $=$ simplify$($ilaplace$($X$))$;

t $=0$:$0\mathrm{.}001$:$3$;

xn $=$ eval$($x$)$;

plot$($t$,$xn$)$