(9.97/(13-1))*(1.5*(1.46-1) (1.5*1.46)/(1.28-1)*(1-1/(8.9^(1.28-1)))-1/(1.37-1)*(1-1/(12.5^(1.37-1)))

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.