The inverse of a bijection is also a bijection

Show that the inverse of a bijective is also a bijection.

The inverse of a bijection is unique

The composition of two bijections is a bijection

Show that the inverse of a bijective function is unique.

If f : A to B and g: B to C are two bijective functions then prove that gof : A to C is also a bijection.

If f and g are two bijections; then gof is a bijection and (gof)^(-1)=f^(-1)og^(-1)

Find the number of bijections from a set A containing 7 elements onto itself.

If f: A to B, g:B to C are two bijective functions then prove that gof:A to C is also a bijective function.

Let A = [-1, 1]. Which of the following functions on A is not a bijection?