Let
\(A = \begin{bmatrix}-1&a\\0&b\end{bmatrix}\)
\(A^2 = \begin{bmatrix}1&a(b - 1)\\0&b^2\end{bmatrix}\) become identity if b = 1 & a be any number.
\(A^3 = \begin{bmatrix}-1&-a(b - 1-b^2)\\0&b^2\end{bmatrix}\) never become identity
\(A^4 = \begin{bmatrix}1&a(b-1)(b^2 + 1)\\0&b^2\end{bmatrix}\) become identity if b = 1 and a be any number.
A2n become identity if b = 1 and a be any number but A2n+1 never become identity.
\(\therefore T_n = \left\{\begin{bmatrix}-1 &a\\0&1\end{bmatrix};a\in\{1, 2, .....,100\}\right\}\)
\(\bigcap\limits_{n=1}^{100} T_n= \begin{bmatrix}-1 &a\\0&1\end{bmatrix};a\in\{1, 2, .....,n^2\}= T_n\)