HP Forums

Hi,

Plotting the function

<< -> X << 0 1 X LN UTPN >> >>

leads to an error message: "UTPN Error: Bad Argument Type". Any suggestions as to why this is happening?

When I store the function above in a variable V and enter it in the command line, it evaluates to a number just fine, e.g., V(1) EVAL leads to 0.5 as expected. But when I use V(X) as the function to be plotted it complains as described above.

This issue is related to having the function LN(X) as the argument to UTPN. Do I need an extra step to make sure LN(X) evaluates to whatever datatype UTPN takes?

Thank you very much for your time.

If you are in approximate mode, then you should be fine. If not, add in a ->NUM right before the UTPN.

TW

Thanks Tim.

Unfortunately, I can't still get it to plot even with ->NUM. The funny thing is that

<< -> X << 0 1 X COS ->NUM UTPN >> >>
or
<< -> X << 0 1 X EXP ->NUM UTPN >> >>

plot as expected. However,

<< -> X << 0 1 X LN ->NUM UTPN >> >>
or
<< -> X << 0 1 X LOG ->NUM UTPN >> >>

refuse to plot giving "UTPN Error: Bad Argument Type". Do log functions need to be treated differently? I have an HP50g.

What's your plot range? Can x be negative? Then ln(x) is complex, and UTPN doesn't like complex numbers.