The total utility from consuming goods x and y is U(x,y) = x'*y^3/t. When the consumption of good x does not change, the change in utility from an increase in the consumption of good x is called the marginal utility of good x. The marginal utilities of goods x and y can be expressed as MUx and MUy respectively.
1) Find the marginal utility for each good.
2) Find the total utility changes when x changes from 100 to 99 and y changes from 200 to 201.