Hmmm... Pedigree of this app is shady...
I bought this app (modest price) because I thought it might be helpful for my high school age kids.
My chief observation is that the information appears to be tables, formulas, and examples culled and pdf'ed from a textbook. And, I might add, the info is far from comprehensive. The screens cannot be magnified using the iPhone's interface, further leading me to believe that this is simply a hack-and-paste job. Scan the inside covers of your kid's high school textbooks and save in your favorite notes or other app and you'll probably come out ahead...
I think the author's intentions were good, but if this is the level of effort required to create marketable iPhone apps, I'm in the wrong line of work.