各位大侠帮帮忙吧，现在有一篇ＡＳＳＩＧＮＭＥＮＴ下礼拜一就要交了，现在才开学３个礼拜，真的都快搞蒙了

a. What effect does a price increase have on the total revenue of the producers?

b. What factors determine the magnitude of the price elasticity of demand?
QUESTION 4
Using supply-and-demand diagrams, show the effect of the following events on the
market for sweatshirts.
a. A hurricane in South Carolina damages the cotton crop.
b. The price of leather jackets falls.
c. All colleges require morning callisthenics in appropriate attire.
d. New knitting machines are invented.

学校说前两个礼拜是试听，所以就去听了ＭＡＲＫＥＴＩＮＧ的课，这个ＥＣＯ根本就还没上课就要让写ＡＳＳＩＧＮＭＥＮＴ．哪位大侠会的话回个贴，这几到题都是关于哪方面的．．．．．多谢了