Solution
= Solution
Because $T$ is positive, the definition of <big O notation> becomes
$$
\boxed{\exists C>0\ \exists n_0\in\mathbb N_+\ \forall n\geq n_0:\quad T(n)\leq Cn^2.}
$$
Here $C$ and $n_0$ are fixed independently of $n$.
= Solution
Because $T$ is positive, the definition of <big O notation> becomes
$$
\boxed{\exists C>0\ \exists n_0\in\mathbb N_+\ \forall n\geq n_0:\quad T(n)\leq Cn^2.}
$$
Here $C$ and $n_0$ are fixed independently of $n$.