Re: DSolving(?) for a given tangent

*To*: mathgroup at smc.vnet.net*Subject*: [mg81379] Re: DSolving(?) for a given tangent*From*: Szabolcs Horvát <szhorvat at gmail.com>*Date*: Fri, 21 Sep 2007 03:07:43 -0400 (EDT)*References*: <fct9c4$r6e$1@smc.vnet.net>

Szabolcs Horvát wrote: > AngleWyrm wrote: >> f[x_] := E^(0.22 x); >> Plot[f[x], {x, 6, 36}] >> >> Which plots a nice escalating curve. >> >> What I would like to know is: Where is the point {x,f[x]} that has a >> 45-degree tangent line; > > f[x_] := Exp[a x] > > Solve[f'[x] == 1/2, x] This should be Solve[f'[x] == 1, x], of course!!!!