How to take the log of an equation? [duplicate]

I am researching a software reliability model that has many parameters that need to be estimated. I want to use a maximum likelihood estimator (MLE) to estimate those parameters, but my model is too complicated to derive the log-likelihood function (namely LL in the following picture) from the likelihood function (namely L in the following picture).

When I try to execute Log[L] in Mathematica, I don't get the expected answer (LL). So my question is, how can I get expected answer after taking the log of the equation? Or can Mathematica not do this operation?

• Please look up Simplify, FullSimplify and ComplexityFunction. Also search this site for useful posts on those. – rm -rf Sep 16 '13 at 16:37
• Can you add the exact code instead the pictures of it ? – Sektor Sep 16 '13 at 16:59
• Sorry, I am rookie in here, so I directly post the link for code in the picture. – user2336074 Sep 16 '13 at 17:16
• I try to input SuperLog[On],but I just get output SuperLog[On]. – user2336074 Sep 16 '13 at 17:34
• @user2336074 Unfortunately the SuperLog thing referenced in the top answer is only available by purchasing the add-on package mathStatica. – Mr.Wizard Sep 16 '13 at 17:41