Which of these functions is continuous everywhere?
f(x)=1/xf(x) = 1/xf(x)=1/x
f(x)=tan(x)f(x) = \tan(x)f(x)=tan(x)
f(x)=sin(x)f(x) = \sin(x)f(x)=sin(x)
f(x)=xf(x) = \sqrt{x}f(x)=x