# Wrong steps in Course 1 Week 2 - More Vectorization Examples

I will refer to the following two screenshots :

and

as you can see, the definition of dz has gone from being (a-y) to a(1-a) which is pointed out in the reading titled Clarification of “dz”. Now, although it’s right in mentioning that
dL/dz in code as dz is (a-y) and da/dz will be a(1-a), I think there is a mistake here.

This is because although the definition of dz is changed whereas dw and db are still xi*dz.
Hope I am making sense.

1 Like

@IshanDave Check this:

Hi,

Thank you for the clarification, I understand there was a confusion with the definition of dz. However, as @IshanDave mentions, I also think that in this slide, it should be written dz= a - y

Thanks,

2 Likes

I agree with this. The clarification only mentions where a(1-a) came from, not whether dz = a(1-a) is the correct use. I also think that dz = (a-y) is what it should be and the clarification should mention that.

2 Likes

@theghks2 agreed, however at this point students should know which `dz` Andrew is referring to.

1 Like