You're looking at Less Wrong's discussion board. This includes all posts, including those that haven't been promoted to the front page yet. For more information, see About Less Wrong.

Daniel_Burfoot comments on Open thread, Feb. 9 - Feb. 15, 2015 - Less Wrong Discussion

6 Post author: MrMind 09 February 2015 09:12AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (321)

You are viewing a single comment's thread. Show more comments above.

Comment author: Daniel_Burfoot 12 February 2015 08:31:32PM 1 point [-]

The key idea to use here is linearization: even if a function is substantially non-linear overall, it is usually going to be linear in the small region around a point. Since the meal price is small compared to income, utility is just a linear function in that region.

If you haven't done the math in a while, it's a good exercise to see that when you do the Taylor approximations for the two functions, they are equal to first order.

Comment author: ciphergoth 13 February 2015 05:59:36PM 0 points [-]

Right, it was by using the Taylor series around the mean I got the approximation based on the variance. Paul pointed out to me you could do this and presumably did this calculation himself already