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Can the master method be applied to the recurrence $T(n)=4T(n/2)+n^2\ lg\ n$ ?Why or why not? Give an asymptotic upper bound for this recurrence.
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it's $n^2log^2n$ ?
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If we apply Master’s Theorem:

$=> n^2logn = n^{log_24}$

$=> n^2logn = n^2$       $… (1)$

In essence, $n^2logn$ is not polynomially greater than $n^2$

Hence, we apply a more generalized Master’s Theorm which says:

If $f(n) = \theta(n^{log_ba}log^kn)$ where $k>0:$

$ => T(n) = \theta(n^{log_ba} \cdot log ^{k+1}n)$

Let me make it little simpler here, it means where you see the log term, multiply again with the log term.

In our case it was:

$=> \mathbf{n^2logn} = n^2$       … From $(1)$

Hence we will multiply $logn$ again to LHS term

Our answer becomes:

$ => \mathbf{n^2logn} \cdot logn$

$ => \mathbf{n^2log^2n}$

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