> Simone P Powell <spowell@iusb.edu> writes:
> I was surprised when I graphed y = abs(log(x)) on the TI-85 veiw screen.
> I was also surprised that the TI-81 and 82 did a better job at graphing
> the function than the 85. The graph is asymtotic to the y-axis, and it
> appears that is what the 81 and 82 is trying to display. However, the
> TI-85 is way off the mark. Can someone tell me how accurate the TI80, 83
> or 92 does on this function?
>
> --
>
> Sam Powell
>
>>>>
Try computing log(-1) on the TI-85. You'll probably get 1.3643764i. The TI-83
will give either that or a NONREAL ANS error, depending on the mode it's in.
The
only difference is in the interpretation of the logarithm function. In general,
when x is negative, the log function returns complex values with the real
component equal to the log of the absolute value of x and the imaginary
component equal to log(e^pi), or 1.3643764i. The TI-80, 81, and 82 can't handle
complex numbers, so they will only graph the log function for x > 0.
Harry