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Symbolic Math Toolbox VS MuPAD: example in advance of the first?

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MATLAB
>> simplify(exp(log10(x)))
ans =
x^(1/log(10))
MuPAD
simplify(exp(log(10,x)), ln)
No effect. How to force MuPAD to simplify truely? I used consider MATLAB Simb.Tbx as a reduced version of MuPAD? That is -- MATLAB calls the MuPAD functions...

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Accepted Answer

Walter Roberson
Walter Roberson on 7 Jun 2011
This is as documented here
Mathematically, log(b, b^y) = y holds true for any real y. This simplification is implemented for the following cases: i) b is a symbolic (indexed) identifier and y is of type Type::Real, ii) b is numerical and y is integer or rational.
and
Note that arithmetical rules such as log(b, x*y) = log(b, x) + log(b, y) are not valid throughout the complex plane. Use properties to mark identifiers as real and apply functions such as expand or simplify to manipulate expressions involving log. Cf. example 4.
So you could possibly use
simplify(exp(log(10,x))) assuming x::real

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Igor
Igor on 7 Jun 2011
Clearly.
But Log of complex value may be account like sin() with periodic term.
Thanks.

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More Answers (2)


Andrei Bobrov
Andrei Bobrov on 6 Jun 2011
in MuPAD
expand(subs(exp(log(10,x)),log(10,x)=ln(x)/ln(10)));
EDIT
rewrite(exp(log(10,x)),ln)

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