Question

without using (10) show and prove that for any whole number use n and for any positive number use y, y^-1+n=y^-n

Answer 1

We have the following expression:

$\begin{gathered} y^{(-1+n)}=y^{-n} \\ \Rightarrow y^{-1}\cdot y^n=\frac{1}{y^n} \\ \Rightarrow y^n=y\cdot\frac{1}{y^n} \\ \Rightarrow y^n=y^{1-n} \end{gathered}$

For this to happen, we need that y = 1 and n can be any whole number.