Opened 2 years ago

Closed 2 years ago

#28638 closed defect (invalid)

taylor() incorrect result

Reported by: gh-MarianD Owned by:
Priority: minor Milestone: sage-duplicate/invalid/wontfix
Component: calculus Keywords:
Cc: Merged in:
Authors: Reviewers:
Report Upstream: N/A Work issues:
Branch: Commit:
Dependencies: Stopgaps:

Status badges

Description

The last term is 3/2, but the correct value is 2 (because sqrt(x+2) is 2 for x = 2).

┌────────────────────────────────────────────────────────────────────┐
│ SageMath version 8.6, Release Date: 2019-01-15                     │
│ Using Python 2.7.15. Type "help()" for help.                       │
└────────────────────────────────────────────────────────────────────┘
sage: taylor(sqrt(x+2), x, 2, 3)
1/512*(x - 2)^3 - 1/64*(x - 2)^2 + 1/4*x + 3/2

Change History (3)

comment:1 follow-up: Changed 2 years ago by chapoton

  • Milestone changed from sage-9.0 to sage-duplicate/invalid/wontfix
  • Status changed from new to needs_review

This answer is correct. Note that the linear term is not written as a multiple of x-2.

comment:2 in reply to: ↑ 1 Changed 2 years ago by gh-MarianD

Replying to chapoton:

This answer is correct. Note that the linear term is not written as a multiple of x-2.

Oh, you're right, I overlooked it. It's little confusing to provide the result in such a “mixed” form.

comment:3 Changed 2 years ago by chapoton

  • Resolution set to invalid
  • Status changed from needs_review to closed
Note: See TracTickets for help on using tickets.