RetroFed Forum

Share your cool maths problems.

Complete a challenge:

Post your solution in comments, if it is exactly the same as OP's solution, let us know.
Have fun.

Post a challenge:

Doesn't have to be original, as long as it is not a duplicate.
Challenges not riddles, if the post is longer than 3 paragraphs, reconsider yourself.
Optionally include solution in comments, let it be clear this is not a homework help forums.
Tag [unsolved] if you don't have a solution yet.
Please include images, if your question includes complex symbols, attach a render of the maths.

Feel free to contribute to a series by DMing the OP, or start your own challenge series.

Welcome to the nostalgia-filled piefed instance of yesteryear.

Open Registration with Application questionnaire.

If you have a question or comment you can post in !meta@retrofed.com or message @DosDude@retrofed.com or @Die4Ever@retrofed.com

In case of downtime and/or emergency, we will post updates on @DosDude@mastodon.social

Some rules we try to uphold:

Be civil. Bigotry is not welcome. This includes (but is not limited to): transphobia, queerphobia, racism, ageism and ableism. We do not promote hate.
Communities need to be Retro or Retro-adjacent.
Please don't upload pornographic content. (use an external image host for that)

Share your cool maths problems.

Complete a challenge:

Post your solution in comments, if it is exactly the same as OP's solution, let us know.
Have fun.

Post a challenge:

Doesn't have to be original, as long as it is not a duplicate.
Challenges not riddles, if the post is longer than 3 paragraphs, reconsider yourself.
Optionally include solution in comments, let it be clear this is not a homework help forums.
Tag [unsolved] if you don't have a solution yet.
Please include images, if your question includes complex symbols, attach a render of the maths.

Feel free to contribute to a series by DMing the OP, or start your own challenge series.

Share your cool maths problems.

Complete a challenge:

Post your solution in comments, if it is exactly the same as OP's solution, let us know.
Have fun.

Post a challenge:

Doesn't have to be original, as long as it is not a duplicate.
Challenges not riddles, if the post is longer than 3 paragraphs, reconsider yourself.
Optionally include solution in comments, let it be clear this is not a homework help forums.
Tag [unsolved] if you don't have a solution yet.
Please include images, if your question includes complex symbols, attach a render of the maths.

Feel free to contribute to a series by DMing the OP, or start your own challenge series.

Welcome to the nostalgia-filled piefed instance of yesteryear.

Open Registration with Application questionnaire.

If you have a question or comment you can post in !meta@retrofed.com or message @DosDude@retrofed.com or @Die4Ever@retrofed.com

In case of downtime and/or emergency, we will post updates on @DosDude@mastodon.social

Some rules we try to uphold:

Be civil. Bigotry is not welcome. This includes (but is not limited to): transphobia, queerphobia, racism, ageism and ableism. We do not promote hate.
Communities need to be Retro or Retro-adjacent.
Please don't upload pornographic content. (use an external image host for that)

	Replies	Author	Score	Last Post
Sticky: A List of all Ongoing Challenge Series	0	siriusmart	1	Wed May 1, 2024 9:36 pm »

[2025/10/29] Inequality (lemmy.world)	0	siriusmart	1	Wed Oct 29, 2025 1:16 pm »
Equalities 1 (hrmacbeth.github.io)	0	scratsearcher 🔍🔮📊🎲	1	Sat Feb 15, 2025 10:30 pm »
[Unsolved] Magic squares and their Inverse (en.wikipedia.org)	0	scratsearcher 🔍🔮📊🎲	1	Sat Feb 15, 2025 9:35 pm »
[solved] A tale of two rabbits	0	joelthelion	1	Sat Feb 15, 2025 5:54 pm »
[2025/01/15] Twice derivative of function (lemmy.world)	0	siriusmart	1	Wed Jan 15, 2025 10:40 pm »
[2025/01/11] Perpendicular of contour lines (lemmy.world)	0	siriusmart	1	Sat Jan 11, 2025 10:37 pm »
[2024/11/06] Derivative with multiple of differential (lemmy.world)	0	siriusmart	1	Wed Nov 6, 2024 11:38 pm »
[2024/08/07] Hypocycloid (lemmy.world)	0	siriusmart	1	Wed Aug 7, 2024 1:06 pm »
[2024/08/04] Extended Euclid's Algorithm (lemmy.world)	0	siriusmart	1	Sun Aug 4, 2024 7:31 pm »
[2024/08/01] Multiple of modulus (lemmy.world)	0	siriusmart	1	Thu Aug 1, 2024 12:31 pm »
[2024/06/30] Decimal expansion for real numbers (lemmy.world)	0	siriusmart	1	Sun Jun 30, 2024 3:08 pm »
[2024/06/28] Approximate log base 2 (lemmy.world)	0	siriusmart	1	Fri Jun 28, 2024 1:50 pm »
[2024/06/02] Horizontal asymptote of the other kind (lemmy.world)	0	siriusmart	1	Sun Jun 2, 2024 4:02 pm »
[2024/05/25] Angle between two vectors (lemmy.world)	0	siriusmart	1	Sat May 25, 2024 7:10 pm »
Coin-flipping game	0	zkfcfbzr	1	Thu May 23, 2024 1:22 am »
[2024/05/18] Not a telescoping series (lemmy.world)	0	siriusmart	1	Sat May 18, 2024 6:29 pm »
Bounding a function (lemmy.world)	0	zkfcfbzr	1	Fri May 17, 2024 11:38 pm »
[Unsolved] [2024/05/17] 1 dimensional gravity (lemmy.world)	0	siriusmart	1	Fri May 17, 2024 5:32 pm »
[2024/05/16] Infinite multiplication series (lemmy.world)	0	siriusmart	1	Thu May 16, 2024 7:53 pm »
[2024/05/15] Differentiability implies continuity (lemmy.world)	0	siriusmart	1	Wed May 15, 2024 9:19 pm »
Solve for x (lemmy.world)	0	zkfcfbzr	1	Wed May 15, 2024 6:54 am »
[2024/05/14] General differential equation (lemmy.world)	0	siriusmart	1	Tue May 14, 2024 7:26 pm »
[2024/05/13] Irrational powers (lemmy.world)	0	siriusmart	1	Mon May 13, 2024 6:29 pm »
[2024/05/09] Sum of n squares (lemmy.world)	0	siriusmart	1	Fri May 10, 2024 7:00 pm »