Re: Fundamental theorem problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg49592] Re: Fundamental theorem problem*From*: pnardon <pnardon at ulb.ac.be>*Date*: Sat, 24 Jul 2004 03:47:22 -0400 (EDT)*References*: <cdqqnb$km6$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Steven Jonak wrote: > I input the command: D[Integrate[Sec[t],{t,1,x^4}],x] expecting to get > 4x^3 Sec[x^4] but instead got a fairly complicated result that doesn't > resemble what one would expect from the Fundamental Theorem of Calculus. > What am I doing wrong? Help! > > S Jonak > "Maintain an even strain." > Try this Simplify[D[Integrate[ Sec[t], {t, 1, x^4}, Assumptions -> {Im[x] == 0, x > 1, x^4 < Ï?/2}], x]] in fact it is usual that you need some assumptions to integrate from 1 to x you need to say that x is real (first) then other specification... that's math life