Which of the following functions is a contraction on [0,1][0, 1][0,1]?
f(x)=xf(x) = \sqrt{x}f(x)=x
f(x)=cos(x)f(x) = \cos(x)f(x)=cos(x)
f(x)=x2f(x) = x^2f(x)=x2
f(x)=1−x2f(x) = 1 - x^2f(x)=1−x2