Context Free Grammar Exercise
For every nonterminal $A$ it always holds that $A \Rightarrow^* A$. This is because $\Rightarrow^*$ is the reflexive transitive closure of $\Rightarrow$. In words, $A \Rightarrow^* \alpha$ is $\alpha$ can be obtained from $A$ by applying zero or more productions.

The similar notation $\Rightarrow^+$ is the transitive closure of $\Rightarrow$, and corresponds to one or more productions. In your grammar, it isn't the case that $T \Rightarrow^+ T$.