I need some help with solving a past exam question. Any help pointing me in the right direction would be apprecited. Thanks.

Question:

a) Find f[0,3] for the following function

f(x) = 1/3 x^3 - x + 1

b) Consider the following function :

f(x) = e^-ax a,x > [0,infiniti]

Find values of a for which f is a contraction .

c) Prove that for all x,y <equalto 0

[2^x - 2^y] <equalto [x-y] ([ = modulus)