What is the relation between half-life and decay constant of a radioactive isotope ?

Write the relation between average life and decay constant of a radioactive atom.

The relation between half life period and decay constant is

Using the equation N = N_(0)e^(-lambdat) , obtain the relation between half-life (T) and decay constant (lambda) of a radioactive substance.

The relation between half life (T) and decay constant (lambda) is