Why does the LOG10 function return an error on SYM objects in MATLAB 6.5 (R13)?

2009 6 27
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When I run the following code in MATLAB 6.5 (R13) :
x = sym('x')
log10(x)
I get the following error message:
??? Error using ==> log2
Function 'log2' is not defined for values of class 'sym'.
Error in ==> C:\MATLAB6p5\toolbox\matlab\elfun\log10.m
On line 17 ==> y = log2(x);
This code works correctly in MATLAB 6.1 (R12) and returns the following result:
ans =
1125899906842624/2592480341699211*log(x)

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 采纳的回答

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This bug has been fixed for Release 14 (R14). For previous releases, please read below for any possible workarounds:
This is a bug in the Symbolic Math Toolbox 2.1.3 (R13).
As a workaround, try the following:
x = sym('x')
log(x)./log(10)
This will return:
ans =
1125899906842624/2592480341699211*log(x)

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