Update Polynomial Tensor example with torch api

[spzala]

Fixes# #3879

Description

torch.pi available since PyTorch 1.8.0 so use it instead of extra math call.

Checklist

• The issue that is being fixed is referred in the description (see above "Fixes #ISSUE_NUMBER")
• Only one issue is addressed in this pull request
• Labels from the issue that this PR is fixing are added to this pull request
• No unnecessary issues are included into this pull request.

The changes made are tested and made sure that it produce the desired output.

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/tutorials/3884

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[spzala]

@pytorchbot label "docathon-2026"

[spzala]

cc @svekars

[sekyondaMeta]

@claude

[claude]

Claude finished @sekyondaMeta's task in 33s —— View job

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Reviewing PR #3884

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Review Summary

LGTM ✅

This is a clean, straightforward change that replaces math.pi with torch.pi and removes the now-unnecessary import math statement. The change is correct and appropriate:

1. torch.pi has been available since PyTorch 1.8.0, and this tutorial already requires a much newer version of PyTorch, so there's no compatibility concern.
2. The removal of import math is correct — there are no other references to math in the file.
3. The blank line removal (going from two blank lines after the import to one) is fine and keeps things tidy.

This makes the tutorial more self-contained by using only the torch namespace, which is a better pedagogical choice for a beginner tutorial focused on PyTorch tensors.

No issues found. Good to merge.

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[spzala]

Thanks @svekars !!