why does my syms appear as error

clc;clear all;format compact;

syms f g

x$1=$input$(\text{'}$puntos para $($x$)?\text{'})$

x$=$linspace$(-8*$pi$,7*$pi$,$x$1)$;

y$1=$input$(\text{'}$puntos para $($y$)?\text{'})$

y$=$linspace$(-4*$pi$,10*$pi$,$y$1)$;

r$=$input$(\text{'}$que funcion desea graficar? f g$\text{'})$;

if r$==$f

f$1=$sin$($x$)$;

plot$($f$1)$

elseif r$==$g

g$1=$sin$($y$)-6$;

plot$($g$1)$

else

disp$(\text{'}$error$\text{'})$

end