33. Incorrect. The answer is true not false. To find the marginal utility of good x,
differentiate U(x,y) with respect to x holding y constant: ¶(-x^{2}
+ 200xy – y^{2})/¶x = U_{x} = -2x + 200y. To find the marginal
utility of good y, differentiate U(x,y) with respect to y holding x constant: U_{y}
= 200x –2y.