Get a refund from bookstore so you can buy weekend's beer supply. Economics is the only field in which two people can get a Nobel Prize for saying exactly the opposite thing. Specifically, Myrdahl and Hayek shared one. A mathematician, an accountant and an economist apply for the same job. Economists do it with Slutsky matrices.
Economists do it discretely AND continuously.
Economists do it on Leontief's table. Heard at the Bocconi university in Milan. Economics is the painful elaboration of the obvious. A Chicago economist died in poverty and many local futures traders donated to a fund for his funeral. Economics has gotten so rigorous we've all got rigor mortis.