3. (6 points) A price-taking firm only uses capital to produce. Its profit maximization problem is axII (k,p,7) = k) rk max (k,p,r) =pf (k) T\\Q;J where p is sales price, k is capital, and r 1s the cosf'o% :capital. Its technology f(k) has the expected shape: f'(k) > 0, f\" (k)