       Why gives Plot[GTK,{q,o,30}] negat. min. at q=15 ? (GTK:=1/3 q^2 - 10 q + 100)

• Subject: [mg2244] Why gives Plot[GTK,{q,o,30}] negat. min. at q=15 ? (GTK:=1/3 q^2 - 10 q + 100)
• From: txp at pi.net (JanHolland)
• Date: Wed, 18 Oct 1995 05:54:59 GMT
• Approved: usenet@wri.com
• Distribution: local
• Newsgroups: wri.mathgroup
• Organization: txp
• Sender: daemon at wri.com ( )

```Hello,

Say  ATC = Average Total Cost := 1/3 q^2 - 10 q + 100

When I give Plot[ATC,{q,0,30}] the resulting graph gives a minimum
below the X-axis at about q=15

When I give q=15 and N[ATC] it evaluates correctly to GTK=25.

Does anyone know what am I doing wrong ?  Thanks for any effort you
take !

------------- GMT 16.15
Jan Holland
-----------
Jan Holland
txp at pi.net
"A fact is a broken dream"

```

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