Using the following Cobb-Douglas production function y=f(x1 ,x2 )=x1^.2 * x2^.8 with unit costs of inputs w1 for x1 and w2 for x2

a. Please graph the isoquant and isocost of this Cobb-Douglas production function?

b. What is the condition for cost minimization that must hold?

c. What is the cost function c(w1 ,w2 ,y)?

d. Show that the cost function exhibits constant returns to scale.