Total differential, level curve. (please check work)

[939]

Homework Statement

For u(x1, x2) = ax1 + bx2

a) find total differential
b) Draw a representative level curve for u = ubar (u with a line over it)
c) Find MRS (marginal rate of substitution)

Homework Equations

u(x1, x2) = ax1 + bx2

The Attempt at a Solution

a)
fx1 = a
fx2 = b
du = fx1dx1 + fx2dx2
du = adx1 + bdx2

b)

c) adx1 + bdx2 = 0
bdx2 = -adx1
-(dx2/dx1) = a/b

∴ MRS = a/b

 

[BruceW]

I don't know economics. But mathematically, your answers look good to me. (I looked up the definition for marginal rate of substitution, and that suggests you have the right answer).

 

[939]

I don't know economics. But mathematically, your answers look good to me. (I looked up the definition for marginal rate of substitution, and that suggests you have the right answer).

Yes, I should've added something about that. Thanks :-).