Show that this model gives diminishing returns to

Question

Label parts a-b clearly

Y = AP^.45I^.55

where,

Y = total output

A = scaling constant

P = physical capital

I = intellectual capital

a. Show that this model gives diminishing returns to physical capital

b. Show that this model gives diminishing returns to intellectual capital I.

c. Show that this model gives constant returns to total capital K = P^.45I^.55

d. Derive the endogenous output growth rate for this model.