# Codercise H.2.1 **URL:** \ **Category:** Codebook\ **Created:** [January 11, 2023, 5:55am UTC](https://discuss.pennylane.ai/t/codercise-h-2-1/2427 "2023-01-11T05:55:49Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Mayu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/mayu/32/3328_2.png) [@Mayu](https://discuss.pennylane.ai/u/Mayu)\ **Post date:** [January 11, 2023, 5:55am UTC](https://discuss.pennylane.ai/t/codercise-h-2-1/2427/1 "2023-01-11T05:55:49Z")
I’m not sure where does it wrong. ![image](https://canada1.discourse-cdn.com/flex012/uploads/pennylane/original/2X/1/175271140504137878e637cdfaeceef02d00974a.png) ---
**Author:** ![Mayu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/mayu/32/3328_2.png) [@Mayu](https://discuss.pennylane.ai/u/Mayu)\ **Post date:** [January 11, 2023, 7:01am UTC](https://discuss.pennylane.ai/t/codercise-h-2-1/2427/2 "2023-01-11T07:01:47Z")
I solved it! I used np.dot instead of \* . ---
**Author:** ![CatalinaAlbornoz](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/catalinaalbornoz/32/1196_2.png) [@CatalinaAlbornoz](https://discuss.pennylane.ai/u/CatalinaAlbornoz)\ **Post date:** [January 23, 2023, 4:41pm UTC](https://discuss.pennylane.ai/t/codercise-h-2-1/2427/3 "2023-01-23T16:41:04Z")
Well done @Mayu! As you realized ‘\*’ is element-wise multiplication, which is not the right kind of multiplication in this case. We need to use matrix multiplication either by using functions or the ‘@’ (at) operator. ---
**Author:** ![Mayu](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/mayu/32/3328_2.png) [@Mayu](https://discuss.pennylane.ai/u/Mayu)\ **Post date:** [January 23, 2023, 5:46pm UTC](https://discuss.pennylane.ai/t/codercise-h-2-1/2427/4 "2023-01-23T17:46:27Z")
I see! Thanks, @CatalinaAlbornoz! 🙂