I am confused about these symbols

Course Q&A Deep Learning Specialization Neural Networks and Deep Learning
1

Hello there,

While I am doing the assignment, I am confused about this symbol.
Screenshot 2024-03-19 at 13.15.13
Is it after the transpose?

Thank you,
Faye.

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2

This is not a transpose. The [1] refers to layer 1 of the neural network, so W[1] refers to the weights of layer 1 of the neural network

3

This is the weight vector after the linear calculation on layer one.

Shape (3,4) means the matrix will have 3 rows and four columns.

Like this:

[[ 1  2  3  4]
 [ 5  6  7  8]
 [ 9 10 11 12]]

Note: #'s here are only for example.

Just to note: Your transpose (W.T) will look like this (of the same matrix):

[[ 1,  5,  9],
 [ 2,  6, 10],
 [ 3,  7, 11],
 [ 4,  8, 12]]

And instead have shape (4,3).

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