# Error in the content: Introduction to Variational Quantum Algorithms

**URL:** <https://discuss.pennylane.ai/t/error-in-the-content-introduction-to-variational-quantum-algorithms/7569>\
**Category:** Codebook\
**Created:** [November 15, 2024, 8:59am UTC](https://discuss.pennylane.ai/t/error-in-the-content-introduction-to-variational-quantum-algorithms/7569 "2024-11-15T08:59:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![quantumel](https://avatars.discourse-cdn.com/v4/letter/q/7ea924/32.png) [@quantumel](https://discuss.pennylane.ai/u/quantumel)\
**Post date:** [November 15, 2024, 8:59am UTC](https://discuss.pennylane.ai/t/error-in-the-content-introduction-to-variational-quantum-algorithms/7569/1 "2024-11-15T08:59:12Z")

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Hi,

I noticed that there is a small error in the course, please take a look at the following enclosure.

It’s about the gradient of f(θ).

Let me know if I’m right or I misunderstood something there.  
Otherwise, the term in the middle becomes 0.

Kindest regards

 ![V.1.x-ErreurCours](https://canada1.discourse-cdn.com/flex012/uploads/pennylane/original/2X/3/30ecce3ad89682aed4d718505837a68e6a55b3fe.jpeg)

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**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:** [November 15, 2024, 8:17pm UTC](https://discuss.pennylane.ai/t/error-in-the-content-introduction-to-variational-quantum-algorithms/7569/2 "2024-11-15T20:17:06Z")

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Hi @quantumel, thanks for pointing this out!

You’re right, we don’t want to make those terms cancel out 😅

We’ll make the fix in the Codebook.  
Thanks for helping us improve it!