Re: Integrate query
- To: mathgroup at smc.vnet.net
- Subject: [mg23397] Re: [mg23361] Integrate query
- From: Matt.Johnson at autolivasp.com
- Date: Fri, 5 May 2000 02:07:39 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
FindRoot should work...
FindRoot[ Integrate[ f[x] ==(fixed fraction), { x, 0, a }], {a, (initial guess)}
]
-matt
"A. E. Siegman" <siegman at stanford.edu> on 05/04/2000 12:59:28 AM
Subject: [mg23397] [mg23361] Integrate query
I have a non-negative analytic function f[x] whose area (integral of
f[x] from 0 to Infinity) is unity.
I want to find the upper limit such that the integral up to that limit
will contain a fixed fraction of the total area, i.e. find a such that
Integrate[f[x], {x,0,a}] == f (f<=1)
The question is, what's the most efficient way to program this, if I
want to find a with fair accuracy, and with a variety of different
functions f[x]?
Thanks . . .