# Building your deep neural network - exercise 2

**URL:** <https://community.deeplearning.ai/t/building-your-deep-neural-network-exercise-2/766172>\
**Category:** Neural Networks and Deep Learning\
**Tags:** week-module-4, coursera-platform\
**Created:** [February 8, 2025, 6:17am UTC](https://community.deeplearning.ai/t/building-your-deep-neural-network-exercise-2/766172 "2025-02-08T06:17:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![PreSam](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/presam/32/48429_2.png) [@PreSam](https://community.deeplearning.ai/u/PreSam)\
**Post date:** [February 8, 2025, 6:17am UTC](https://community.deeplearning.ai/t/building-your-deep-neural-network-exercise-2/766172/1 "2025-02-08T06:17:13Z")

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Hi,  
I have a doubt. Why do we use double brackets for the bias term: np.zeros(( )) while we use only one for the weights: np.random.randn ( )?

_{moderator edit - solution code removed}_

Thank you  
Prejith

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**Author:** ![TMosh](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/tmosh/32/9321_2.png) [@TMosh](https://community.deeplearning.ai/u/TMosh)\
**Post date:** [February 8, 2025, 7:13am UTC](https://community.deeplearning.ai/t/building-your-deep-neural-network-exercise-2/766172/2 "2025-02-08T07:13:17Z")

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From the definition of the np.zeros() function:

 ![image](https://global.discourse-cdn.com/dlai/original/3X/2/2/2244a3449b86ee2a3c8c8f988640203f7507df16.png)

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<div class="post-metadata">

**Author:** ![PreSam](https://sea1.discourse-cdn.com/dlai/user_avatar/community.deeplearning.ai/presam/32/48429_2.png) [@PreSam](https://community.deeplearning.ai/u/PreSam)\
**Post date:** [February 8, 2025, 8:59am UTC](https://community.deeplearning.ai/t/building-your-deep-neural-network-exercise-2/766172/3 "2025-02-08T08:59:40Z")

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Thank you