C2-W3 "classification with neural network" videos

I’m wondering whether the results showed at 6:22 of the video “classification with neural network: minimizing log loss” are accurate:

Based on the neural network drawing, w_{21} is the weight of x_2 for the perceptron 1 (in red). So the chain rule for \frac{\partial L}{\partial w_{21}} should be:
\frac{\partial L}{\partial \hat y} \cdot \frac{\partial \hat y}{\partial z} \cdot\frac{\partial z}{\partial a_1} \cdot \frac{\partial a_1}{\partial z_1} \cdot\frac{\partial z_1}{\partial w_{21}}

The last term should be equal to x_2, not x_1 contrary to what’s written on the slide.

Am I missing sth?

Hi @Pablo_Rougerie

Thank you for sharing your observation! Could you please be more specific about the issue you’re noticing? If possible, providing additional details or screenshots of the network diagram and the exact steps in the video you’re referring to would be very helpful.