Indifference Curve, Budget Line & Optimal Utility

A household's utility over two consumption goods x and y is U= U(x,y) = xy.

1. Describe the household's indifference curve for U = 1 for values of x and y less than 3 (ie. the curve containing all combinations of x and y such that U(x,y)=1.

Now assume that the household's wealth is w=4 and that the prices of the goods are px = 2 and py = 2.
2. How many units of x can the household consume at most if it does not consume any y?
3. Describe the household's budget line and its relationship to the indifference curve.
4. What is the household's optimal consumption bundle?
5. What is the Marginal Rate of Substitution (MRS) between the two goods?

Note the budget constraint can be written as 2x + 2y = 4

6. Solve this budget constraint for y and substitute it into the utility function to obtain an expression for utility that depends on x only.
7. Maximize this utility to obtain the optimal amount of x. (Take the derivative of this expression with respect to x, set the derivative equal to zero, solve for x)
8, Find the optimal amount of y by using the result for x.
9. How does this optimal consumption bundle compare to the one found graphically.