In: Economics
The demand and supply function are given by 2P + 3QD = 66 5P – 2QS = 13 Find the equilibrium price and quantity using inverse matrix method.
The equilibrium quantity will be where the Quantity Demanded=Quantity Supplied. So, QD=QS. Lets just represent it with Q in that case. So the equations become
2P+2Q=66
5P-2Q=13
So, the coefficient matrix becomes
A=
The variable matrix is
X=
The constant matrix is
B=
Setting AX=B, we get
=
Now we need to calculate the inverse of the matrix. We know that the inverse is given by
Using this, we get the inverse. First lets calculate 1/(ad-bc). Putting values in from the coefficent matrix, we get
1/(-4-10)=-1/14. Now getting the inverse matrix.
=-1/14
=
Now we multiply both sides of the equation with A-1
Since the left side is getting multiplied by its own inverse, they will cancel out. Multiplying the two matrices on the right side, we get
Hence,
Equilibrium Price=79/7=11.286
Equiibrium Quantity=152/7=21.714