4. A consumer has a utility function u(X₁, X₂) = 1/{(1/X₁) + (4/X₂)}, with prices of the two goods PX₁ and PX₂ respectively. If his total income is given by m: (10 marks)

(a) Find this consumers Marshallian demand function for each good. (4)

(b) Find this consumers indirect utility function. (3)

(c) Find this consumers expenditure function. (3)