Uniform continuity — checking three named functions

Suppose that $f_1,f_2,f_3$ are functions defined by $f_1(x)=x^2, 0\le x<\infty$; $f_2(x)=\cos(x), 0\le x\le\pi/2$; and $f_3(x)=\sin(x)/x$ for $x\neq0$, $f_3(0)=1$. Which of the above functions is/are uniformly continuous on their respective domains?