Exponential inequalities
10-10-2015, 11:58 AM (This post was last modified: 10-10-2015 12:00 PM by parisse.)
Post: #3
 parisse Senior Member Posts: 1,317 Joined: Dec 2013
RE: Exponential inequalities
The solver can solve polynomial-like equations/inequations. Unfortunately there is no easy way to reduce all equations/inequations to a polynomial. But most of the time, you can help the CAS by calling the right pre-simplification command. Here you can do
a:=tsimplify(2^(3*x-1)+2^(6*x-2)-2^(3*x+3)-(4^(3*x-2))
This will express the inequation in terms of the minimum possible independant "variables", here 1, hence the inequation becomes polynomial-like, then
solve(a<0)
will return the exact answer.
The approx answer is partially wrong because the floats are too small for x negative.
Remember: the calc computes very fast but it is stupid, humans do not compute fast but humans know what to do, a typical situation where both can cooperate!
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 Messages In This Thread Exponential inequalities - Aries - 10-09-2015, 10:54 AM RE: Exponential inequalities - roadrunner - 10-10-2015, 10:35 AM RE: Exponential inequalities - parisse - 10-10-2015 11:58 AM RE: Exponential inequalities - Aries - 10-11-2015, 10:20 AM RE: Exponential inequalities - Aries - 10-17-2015, 09:06 AM RE: Exponential inequalities - Tim Wessman - 10-10-2015, 01:54 PM RE: Exponential inequalities - Aries - 10-11-2015, 06:39 AM RE: Exponential inequalities - roadrunner - 10-10-2015, 11:03 PM RE: Exponential inequalities - Aries - 10-11-2015, 10:23 AM RE: Exponential inequalities - parisse - 10-17-2015, 04:15 PM RE: Exponential inequalities - Aries - 10-25-2015, 10:53 AM

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