next question on simplify
09-18-2017, 03:29 PM
Post: #1
 Hans S. Junior Member Posts: 38 Joined: Aug 2017
next question on simplify
what is the idea behind the following beheavior?
solve(8^(n+2)-8^(2*n)=240,n) --> (2/3, (ln(15)+2*ln(2))/(3*ln(2)) -- ok, that's fine, next step

simplify(ln(15)+2*ln(2))/(3*ln(2)) --> ln(15)+2*ln(2))/(3*ln(2) -- oh, that's not so fine.

What makes the prime acting like this? simplify(ln(15)+2*ln(2)) works well and says ln(60).

Beheavior like this in algebraic or textbook mode, simplify maximum, non, minimum setting, and I also tried all the other checkboxes etc. And yes, I used enough brackets, even if I forgot some here.

As I wrote: what is the idea behind? Shouldn't the maximum level for simplify just say (on the "solve" level) "2/3, ln(60)/3*ln(2)"? and leave the less elaborated answers to the other level(s)?
Or is this just an issue with the "/"? Or am I simply stupid and didn't see the wood for the trees?

Thanks
Hans
09-18-2017, 04:02 PM
Post: #2
 parisse Senior Member Posts: 1,093 Joined: Dec 2013
RE: next question on simplify
(ln(15)+2*ln(2))/(3*ln(2)) and ln(60)/(3*ln(2)) have both two "variables", ln(15) and ln(2) or ln(60) and ln(2). That's why simplify does not collect the logarithms. Run lncollect to do that.
Unfortunately there is no universal way to declare something more simplified than something else.
09-18-2017, 04:28 PM
Post: #3
 Hans S. Junior Member Posts: 38 Joined: Aug 2017
RE: next question on simplify
(09-18-2017 04:02 PM)parisse Wrote:  lncollect to do that.
Thank you very much, that is the solution I missed. ... but the ubiquitous "simplify" soft-key is so alluring...
Hans
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