How many tablets should the pharmacy give marilyn to fill the isoniazid for 45 days? (show your work)

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

I'll give brainliest if you answer right : )

Which type of graph would allow us to quickly see how many students between 100 and 200 students were treated?