Hello, I'm beginner with Mathematica and trying to get the basics. I try to use the function called "Simplify". I try to simplify a function Abs(Cos(x)) on 2 different intervals where the result is positive. Thus, I would expect the Simplify function to provide Cos(x) as the result in both cases, exepect that it works inly for one of those intervals :
Do you please have an idea why ine the first case, result is not Cos[x] ?
Thanks for kind help
Best Regards
@Morgan Bourgeois, Welcome to Wolfram Community! Please make sure you know the rules: https://wolfr.am/READ-1ST
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int = Integrate[1/(x^3 - 1), x]; Map[Framed, int, Infinity]
Even FullSimplify is disappointing:
FullSimplify
FullSimplify[Cos[x] == Abs[Cos[x]], 3 Pi/2 < x < 5 Pi/2]
Reduce seems to know better:
Reduce
Reduce[Cos[x] == Abs[Cos[x]] && 3 Pi/2 < x < 5 Pi/2, x] Reduce[Cos[x] == Abs[Cos[x]], x, Reals]
