I believe the last video of week 2 has an error:

At 5:13 we are seeing Gradient Descent for the last sample, i.e. from N-1 to N, so the slide should show:

[**m_n-1, b_n-1**] → [m_n, b_n] = [m_n-1, b_n-1]*…

but it is showing the following:

[**m_n, b_n**] → [m_n, b_n] = [m_n-1, b_n-1]*…