When to add and cancel logarithms

[A.J.710]

I don't have a single homework question but a general one that will help me out tonight. I am taking calculus one college level and we are reviewing logarithms and I am really having trouble. I just don't understand how we are supposed to know where to add and cancel them.

It seems that at certain points in the math you just add a logarithm for it to cancel something out in a later time in the problem. This is really confusing me.

What are some good tactics to approach the problems when dealing with this type of math?

Thanks

 

[johnqwertyful]

It's basic log identities. If you google "logarithm identities" there will be a nice wiki page and some good images. Just make sure you learn the identities and understand them.