23.4 As in Example 23.2, suppose trees are produced by applying one unit of labor at time 0. The value of the wood contained in a tree is given at any time (t) by f(t). If the market wage rate is w and the instantaneous rate is r, what is the PDV of this production process and how should t be chosen to maximize this PDV?

a. If the optimal value of t is denoted by t*, show that the no-pure-profit condition of perfect competition will necessitate that Can you explain the meaning of this expression?