long run - allows for 2 (or more) variable inputs
- diminishing marginal returns shown by drawing horizontal or vertical line through isoquant map
- shows that each increased unit of capital or labor adds less and less to the total output
marginal rate of technical substitution (MRTS) - like MRS for consumers
- amount of capital that can be decreased by an extra unit of labor, for a given output level
- MRTS = -DK/DL = MPL/MPK
- MP = marginal product (partial derivatives of the production function w/ respect to either labor L or capital K)
- units of labor decrease the required capital less and less >> diminishing MRTS
- isoquants are convex >> magnitude of the slope decreases (gets more flat) >> ratio of capital (vertical axis) to labor (horizontal) falls
- isoquant
- equivalent changes in labor lead to less and less change in capital >> diminishing MRTS