The Integration Expansion

Normal sudoku rules apply. A pink line contains a set of consecutive digits in any order, without repeats. Box borders divide a blue line into segments with the same sum. Two cells connected by a green line have a difference of at least 5. Digits in a cage sum to the indicated total. Cells joined by a black X or V sum to 10 (X) or 5 (V). The puzzle includes two straight 2-cell pink lines and two straight 2-cell green lines.

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Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times crossword championship and twice Senior World Champion in Sudoku, and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.

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#solvingsudoku #logicpuzzles
▶ Contents ◀
0:00 Theme Music & News around the channel
3:58 Rules of today’s puzzle
5:00 Start Of Solve - Let's Get Cracking!

[pseudospinhalf]

There's a hidden secret. The integral has its limits marked since the integral from 1 to 5 of x^3 is the sum of the digits under the curve.

[MarushiaDark]

Mark proving he's a sudoku grandmaster by deliberately ignoring the given 1 that would have disambiguated the green x and then proceeding to finish the rest of the puzzle without it in under 20 minutes.

[petermawhorter]

Took me 01:18:30, which is actually really fast in my world, and this one was both fun and very smooth.

[y_prime]

solved in 5:20 - the sum of the killer cages (the "area under the curve") is 156, which is indeed the integral from 1 to 5 of x^3 dx. very nice detail

[artyheartylife]

Your photoshop "skills" are HILARIOUS! And the thumbnails shows both expressions that appeared on MY face when I saw it!😂

[mrgristle]

It's pretty neat that the solution to the definite integral matches the sum of all the cages (156)

[David_K_Booth]

The grid gave me a laugh when I opened the puzzle. This is very approachable - recommended for all skill levels.

[johncox]

I took a completely different approach to this puzzle. Just worked the cages/region sum line until I had the bottom half of the puzzle done. Then I worked on the top half.

[LednacekZ]

7:18 for me. 2 quite easy sudoku today. nice to see something for beginners once in a while.

[JohnPretty]

14:45 Mark, those in box 6 had to be a 79 pair anyway because of the 5 you had placed in box 4.

[peachesa]

@16:20 the easier way to think about the 17 cage is that it has the 1 and must also have a 2 (from the 257) so the other two digits are 14. If one is a 7 then it's 2 7s which breaks. So it's a 5 and 9.

[yashmehta]

21:07
Unbelievably beautiful for such a simple puzzle!

[DamienJones-umcr]

Two very approachable puzzles today lovely

[Coyotek]

10:00 ... I love the theme!

Nice puzzle!

[praematura]

Wonderfully fun puzzle, completed in 8:56 (conflict checker off). Missed the hidden secret, but I will admit my calculus is a bit rusty nowadays. 😄 Many thanks to Evan for it!

[markp]

9:18 finish. I made an error putting in a number and thought that I had broke everything. I was prepared to rewind it all when I noticed that I had typed 6 instead of 8 in a cell. A quick change to a few pencil marks and I was moving again. Fun fun fun!

[donaldsnyder]

23:45 for me.

Fun puzzle, very nice.

[Aliessil]

Finished in 13:40, I'd definitely call his approachable!
Not done integrals in a time, not even sure I remember how, any more 🤔

[mudscuffer]

18:42 for me. Don't feel I was very optimized in my solving, but it flowed nice enough.

[RichSmith]

Mark, do you have an opinion on Simon's use of blue for high digits in his video today? I long ago adopted your colouring scheme of blue for low and orange for high, and I find it quite disconcerting when Simon uses blue for high digits. 🙂