In introductory and intermediate microeconomics courses, students are taught about production functions and cost functions but rarely are they shown a direct link between production and cost. If we assume production is Cobb-Douglas (CD), then the CobbDouglasProductionToCost.xlsx Excel file shows the link between short-run (SR) and long-run (LR) production and cost in geometric detail. The CDCosts sheet uses three interactive linked figures: I. Isoquant/Isocost; II. Total costs (TC); and III. Per-unit costs (ATC, MC, and AVC). This file shows four hypothetical SRs and their LR counterparts. Sliders for, a, b, c, w and r allow the user to interact with the CDproduction function, Q=aLbKc, subject to input prices w=PLabor and r=PCapital. Individual SR and LR curves in each figure are controlled by click-boxes. Two supplementary interactive sheets allow students to vary a, b, c, and w and view the results. CD Production provides three perspectives: an isoquant map, a 3-D side view focuses on returns to scale, and a 3-D frontal view focuses on SR production, marginal productivity and relative factor productivity. TP(L) to VC(Q) links SR production to variable cost. Three textual sheets and a Handout sheet round out the file. StudentQuestionsAndNotes provides students 41 questions in three topic areas; CD production, CD cost minimization, and CD costs, as well as notes which help students describe how cost curves change when a, b, c, w, or r change. These notes focus on how to describe a curve by its shape and placement. The Answers sheet may be deleted prior to student distribution. InstructorNotes provides details for how to use the file for classroom and homework purposes as well as the equations behind the figures. Students can gain substantial insights from the geometry of these curves without ever being exposed to the equations that created them
