A square matrix is singular whenever:

(a) Solve the recurrence equations
$$\,\,\,\,\,\,\,\,\,T\left( n \right) = T\left( {n - 1} \right) + n$$
$$\,\,\,\,\,\,\,\,\,T\left( 1 \right) = 1T$$
(b) What is the generating function?
$$\,\,\,\,\,\,\,\,\,G\left( z \right)$$ for the sequence of Fibonacci numbers?

(a) How many binary relations are there on a set A with n elements?

(b) How many one - to - one functions are there from a set A with n elements onto itself

A critical region is: