Here's the question you clicked on:
zane120000
session 68:Problems: Green's Theorem and Area (PDF) http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/3.-double-integrals-and-line-integrals-in-the-plane/part-c-greens-theorem/session-68-planimeter-greens-theorem-and-area/MIT18_02SC_pb_68_quest.pdf And the answer is here: http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/3.-double-integrals-and-line-integrals-in-the-plane/part-c-greens-theorem/session-68-planimeter-greens-theorem-and-area/MIT18_02SC_pb_68_quest.pdf Can I make N =x^3/3 and M=-y^3/3? If not,Why?
If you multiply N and M by density then you can. There is more than one answer to this problem, they just give you the easiest one.