The flexibility matrix for a beam is given as \(\left| {\begin{array}{*{20}{c}} b&a\\ d&c \end{array}} \right|,\) which of the following represent the correct relation between b and c, given that b and c are non-zero real numbers.
1
b = c, b < 0, c < 0
2
b ≠ c, b > 0, c > 0
3
a = d, b > 0, c < 0
4
a = d, b > 0, c > 0