The limit lim_(x->0)sin(1/x) does not exist. You can proove this taking two sequences such as a_n=1/(2pin) and b_n=1/((2n+1)*pi) and replacing into the value of x.Hence
sin(1/(1/((2pin))))=sin(2*pi*n)=1 or -1.Hence the values of the limits both sequences are different such limit does not exist