Which of these functions has a jump discontinuity?
f(x)=xf(x) = xf(x)=x
f(x)=∣x∣/xf(x) = |x|/xf(x)=∣x∣/x
f(x)=1/x2f(x) = 1/x^2f(x)=1/x2
f(x)=sin(x)f(x) = \sin(x)f(x)=sin(x)