Re: Calculation of powers (TI-86)
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Re: Calculation of powers (TI-86)
>Hi all!
>How exactly does a TI-86 calculate powers? I think it has something to
>do with logarithms.
>Thanks,
>Kevin DeGraaf
[snip]
>From: Matt Maurano <mtm@MAURANO.COM>
>Probably the same way we do: 2^5=2*2*2*2*2
>If you want to know how to do it, you can either use the
>log button [or] the ^ button.
[snip]
>Is it possible that the question was referring to exponents in
>general, including fractional exponents?????
>If so, then the answer is not so simple. Computing 5^(7.2) is not as
>easy as multiplying 5 by itself 7.2 times! But, 5^(7.2)=(5^7)*(5^.2).
>5^7 is easy. 5^.2 is probably computed using curve fitting techniques
>from numerical analysis.
>Scott
[snip]
>I believe that the original post was asking for the formula:
> a^b = e ^ (b*ln(a)).
>e.g., 2^7.2 = e ^ (7.2*ln(2) = e^(4.990...) = 147.03...
>The TI-86 has ways to compute ln( ) and e^( ), and of course
multiplication
>is relatively easy, so it can handle (nearly) any exponential
expression.
>Darryl K. Nester [nesterd@bluffton.edu]
Hi all.
The first reply was _not exactly_ what I was looking
for. Someone who doesn't know how to use the (^) key
shouldn't own a calculator.
I am more interested in the the second answer. (Thanks Scott!)
We will be discussing this in class in a few days, and I'd like as
much technical (yet useful) info as possible.
The last reply helps, too. (Thanks Darryl!) I was aware of
the formula (infamous "log law #3" plus some "tricky" mathematics),
but it seems that we are back to square one. How does the 86
calculate e to non-integer/negative powers? I'm thinking there is an
easy way to do this with higher math than I know (Functions, Stats,
and Trig). Also, how are natural logs (and common ones too, for that
matter) calculated? Finally, what about negative bases (can't take the
ln() of those, if I'm not mistaken)?
Thanks a lot to all,
Kevin DeGraaf (TI-86)
Class of 1999, Unity Christian High School
EMail: kdegraaf@NOSPAM-juno.com (I think you know what to do.)
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