Use Exercise 1.32 to transform the indirect utility function to
v*(p,y) = G inverse (v(p,y)).
Then v*(p',y bar) - v*(p,y bar) = A(p') - A(p).
Split the integral using p < p' < p zero to get the result.
The utility loss is the negative of an area under a demand curve and this is money.
But I have a problem with 1.49(a). There is only one good so we can immediately write down the demand function as x(p,y) = y/p and this has an income elasticity of one. But this messes up the interpretation of nu.
Puzzled? So am I!