Re: Why gives Plot[GTK,{q,o,30}] negat. min. at q=15 ? (GTK:=1/3 q^2 - 10 q + 100)
- To: mathgroup at smc.vnet.net
- Subject: [mg2220] Re: Why gives Plot[GTK,{q,o,30}] negat. min. at q=15 ? (GTK:=1/3 q^2 - 10 q + 100)
- From: nns at justnt.wineasy.se
- Date: Tue, 17 Oct 1995 02:33:32 -0400
- Organization: None
In article <45d1n0$63m at ralph.vnet.net>, txp at pi.net says...
>
>Say GTK = ATC = Average Total Cost := 1/3 q^2 - 10 q + 100
>
>When I give Plot[GTK,{q,0,30}] the resulting graph gives a minimum
>below to X-axis at about q=15
>
>When I give q=15 and N[GTK] it evaluates correctly to GTK=25.
>
>What am I doing wrong ? Thanks for any effort you take !
>
The horizontal plot axis is probably not y=0. You can force it to be using
the AxesOrigin option. Try this:
Plot[GTK[q], {q, 0, 30}, AxesOrigin -> {0,0}]