Let [0,1] ---> R be bounded. Let f be decreasing. By consideration of the sequence of dissection (Dn) of [0,1] show that f is integrable.

Let E > 0. Then for all N such that s(Dw) < E.

Hence it satisfies Riemann's criteria for integrability.

Can some please help me with this question, as my answer as it stands is rubbish and obviously too short, but I don't see what else to say

Thanks in advance!