Desired consumption and investment are
Cd= 4000-4000r+0.2Y
Id= 2400-4000r
As usual, Y is output and r is the real interest rate. Government purchases are 2000.
(a) Find the equilibrium value of the real interest rate if Y =10000.
(b) Find the equilibrium value of the real interest rate if Y = 10200.
(c) Graph the IS curve for this economy