Decide which of the functions $\displaystyle f_n$ : [0,1] $\displaystyle \rightarrow$ R with n = 0,1,2, defined by setting:

$\displaystyle f_n(x)$ :=

$\displaystyle (x^n)sin(\frac{1}{2}$ if $\displaystyle 0 < x \leq 1$

0 if x = 0

are Riemann integrable on [0,1].

more help please