Re: integrate problem
- To: mathgroup at smc.vnet.net
- Subject: [mg98854] Re: integrate problem
- From: dh <dh at metrohm.com>
- Date: Mon, 20 Apr 2009 19:08:21 -0400 (EDT)
- References: <gshft4$c0o$1@smc.vnet.net>
Hi Sean, consider: Integrate[1/(s[t] + a), t] here the integration variable is t and s[t] is a unknown function. Therefore the argument, that contains an unknown function s[t], can not be integrated. In Integrate[1/(s[t] + a), s[t]] the integration variable simply has a funny name of "s[t]" Daniel sean_incali at yahoo.com wrote: > I'm having some issues understanding this... Following works as > expected. > > s is the variable in time. a is a parameter. > > Integrate[1/(s + a), s] > > gives Log[a + s] > > But the following gives the integral itself. > > Integrate[1/(s[t] + a), t] > > If the function that needs to be integrated w.r.t time is 1/(s[t] + > a), how do I accomplish that? It seems like if integrate it wrt to s > [t] it will work. > > Integrate[1/(s[t] + a), s[t]] > > > But does that sound about right? > > Any thoughts appreciated. > > Sean >