In the closed form solution to multivariate linear regression, why do we use the pseudo-inverse of instead of the simple inverse?

Question

In the closed form solution to multivariate linear regression, why do we use the pseudo-inverse of    instead of the simple inverse?

Accepted Answer

To ensure the solution can be found even if    is not invertible.

Answer

To make the solution more accurate.

Answer

To decrease the computational complexity.

Answer

Because it is easier to compute than the simple inverse.

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