1. What is \(2^{-1} + 2^{-2} + 2^{-3} + 2^{-4} + 2^{-5} + 2^{-6} \pmod{13}\)?
This -1 represents inverse in modular arithmetic. However, what does anything greater than that mean? ex -2, -3. I don't understand this so someone please help!
2. If \(f(x)=\dfrac{x-3}{x-4}\), then for what value of x is \( f^{-1}(x)\) undefined?
Inverse functions, I don't know what to do to make the inverse of \(f(x)\) undefined.
