lim[x->0] (e^x-e^(-x))/sinx
=lim[x->0] (e^x-e^(-x))/x * lim[x->0] x/sinx
=lim[x->0] (e^x-e^(-x))/x
=lim[x->0] (e^x-1)/x + lim[x->0] (e^(-x)-1)/(-x)
=2
lim[x->0] (e^x-e^(-x))/sinx
=lim[x->0] (e^x-e^(-x))/x * lim[x->0] x/sinx
=lim[x->0] (e^x-e^(-x))/x
=lim[x->0] (e^x-1)/x + lim[x->0] (e^(-x)-1)/(-x)
=2