target sells sweaters and sneakers in the ratio 1:3.The store sold 9 sweaters yesterday. How many sneakers were sold?

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?

This is about circle theorems. someone asap : (

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x