We prove that the long run cost function is a power function of output, and point out the special relationship between long run marginal cost function and long run average cost function.

You see, some things may cost a bit more in the short-run, but be worth it in the long-run.

This week President Obama said the obvious: that wealthy Americans, many of whom pay remarkably little in taxes, should bear part of the cost of reducing the long-run budget deficit.