3. A function is called increasing on an interval I iff it satises the property: if 9:1, 2 E I are such that 9:1 2 9:2, then f{I1)$ H332). (a) Using the Mean Value Theorem, prove: if f'{:1:) 2 0 on an interval I, then f is increasing on I. Hint: 1'1 E :32 is equivalent to saying 3:2 2:1 2 Cl. (1)) Use the theorem to nd the intervals on which the function f(:r) = 2:3 33: is increasing