Let f : X → Y be an invertible function. Show that the inverse of f-1 is f, i.e., (f-1)-1 = f.
Let f : X → Y be an invertible function.
Then, there exists a function g: Y → X such that gof = IX and fog = IY
Here, f-1 = g.
Now, gof = IX and fog = IY
⇒ f-1 of = IX and fof -1= IY
Hence, f-1 : Y → X is invertible and f is the inverse of f-1
i.e., (f-1)-1 = f.
Let \( A = \{0,1,2,\ldots,9\} \). Let \( R \) be a relation on \( A \) defined by \((x,y) \in R\) if and only if \( |x - y| \) is a multiple of \(3\). Given below are two statements:
Statement I: \( n(R) = 36 \).
Statement II: \( R \) is an equivalence relation.
In the light of the above statements, choose the correct answer from the options given below.

