1. The production function expresses the relationship between inputs like labor, capital, land, etc. and the quantity of output produced. It defines output as a function of various inputs.
2. Cobb-Douglas production functions take the form Y=(AK^x L^(1-x)) and model output (Y) as a function of capital (K) and labor (L). They assume constant returns to scale and that factors are substitutable up to a limit.
3. Isoquants represent combinations of two variable inputs, like capital and labor, that produce the same level of output. They are used to analyze least-cost input combinations that maximize producer profit or minimize costs.