問題 :
The utility of A(aconsumer/borrower)is U(C1,C2)=C1C2, where C1 is the
consumption today and C2 is the consumpyion tomorrow. A has $Y1 today
and $Y2 tomorrow, Y1<Y2. To simplify, assume that interest rate is r＝0
and therefore the budget constraint is C1+C2=Y1+Y2. The consumer has a
credit limit of $q so that C1-Y1<=q. The utility maximization problem is
: max C1C2
subject to : C1+C2=Y1+Y2, C1-Y1<=q
(a) State the Lagrangian of the problem and the K-T conditions
(b) Find the solution (there 2 cases)
第一小題没什麼問題，但不懂第二小題為什麼有兩個cases
希望大家解答，謝謝:)