Re: Derivative help
- To: mathgroup at smc.vnet.net
- Subject: [mg39160] Re: [mg39139] Derivative help
- From: Tomas Garza <tgarza01 at prodigy.net.mx>
- Date: Fri, 31 Jan 2003 19:57:21 -0500 (EST)
- References: <200301310936.EAA07518@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
The problem is with your syntax. You must learn about the use of parentheses, which play specific roles in Mathematica. Furthermore, the assignment f = "something" doesn't leave f as a function of x, but rather as a name for a symbol. And of course you may not evaluate the derivative of a symbol. What you must do is a proper definition of f as a function of x, such as In[1]:= f[x_] := Log[x]^x Then In[2]:= f'[x] Out[2]= Log[x]^x*(1/Log[x] + Log[Log[x]]) which is what you want (I presume). I strongly recommend that you spend a few weeks reading, from beginning to end, at least the first part of The Mathematica Book, A Practical Introduction to Mathematica. Sections 1.2.5 and 1.7.1 therein are especially relevant to your present problem. Tomas Garza Mexico City ----- Original Message ----- From: "Steve Chiang" <stevezx at attbi.com> To: mathgroup at smc.vnet.net Subject: [mg39160] [mg39139] Derivative help > Hi, all. I'm new to Mathematica. I went to the help section for my > question but it only further confused me. I'm basically trying to take the > first derivative of (ln(x))^x. Here is my syntax: f = (ln(x))^x. But then > when I evaluate f ', it says nothing but ((ln(x))^x)' which is nothing new. > Is this because I didn't specify bounds and that the function may be > discontinuous over the default bounds in Mathematica? > > Thanks > > >
- References:
- Derivative help
- From: "Steve Chiang" <stevezx@attbi.com>
- Derivative help