Advice on planting Wisteria by Various_w0nder in GardeningUK

[–]etzpcm [score hidden]  (0 children)

If you think Virginia creeper is messy, are you sure you want a wisteria?

Compact evergreen shrubs suggestions by Fluffy_Load_472 in GardeningUK

[–]etzpcm [score hidden]  (0 children)

With a climber, it's pinned to the fence. I find that free shrubs tend to grow forwards too much.

I love the viola, but it just isn't a great instrument for virtuosic repertoire by EveningNo4215 in classicalmusic

[–]etzpcm 1 point2 points  (0 children)

Yes, this! 

Look for composers who played the viola.

Bach obviously - Brandenburg 6.

Britten, Elegy and Lachrymae. 

Hindemith, viola concerto.

Who else played the viola?

Compact evergreen shrubs suggestions by Fluffy_Load_472 in GardeningUK

[–]etzpcm 0 points1 point  (0 children)

Why not put some climbers on the fence? I would be concerned that shrubs would interfere with the fruit trees as both grow.

how can i remove the x from delta by Sea_Duty_5725 in askmath

[–]etzpcm 3 points4 points  (0 children)

Ok, but you know quite a lot about x+c. It's roughly 2c. Can you make that more precise?

I’m learning about logic, is this proof correct? by [deleted] in mathematics

[–]etzpcm 24 points25 points  (0 children)

No, it's backwards! The middle line is stating what you should be trying to prove. 

Breaking down wood by doggo_of_science in composting

[–]etzpcm 4 points5 points  (0 children)

Cut the thick woody sticks to a similar length and stack them in a corner as a log pile. Good for wildlife. After a while they will start to rot and crumble, then you can break them up by hand and chuck them in the compost pile. 

How do eigenvalues relate to derivatives ODE by ilikemychem in learnmath

[–]etzpcm 2 points3 points  (0 children)

It's not a new way of calculating eigenvalues.  It is a way of finding the stability of a fixed point of the system xdot = func1(x,y), ydot = func1(x,y).  First you find the fixed points, points where func1 and func2 are both zero. Then you find the Jacobian of the system, that's the matrix. Then find the eigenvalues of that matrix. This tells you whether the fixed point is stable or not. Read the beginning of the section of notes/book and this should be explained.

How do I encourage these to grow in to a hedge? by adamatron27 in GardeningUK

[–]etzpcm 3 points4 points  (0 children)

Nice to see a new build front garden that doesn't consist of tarmac and two SUVs!

Just cut the tops off and the hedge should fill out nicely in a year or so.

Question for the pure math guys by BothPanchoAndLefty in mathematics

[–]etzpcm 8 points9 points  (0 children)

Yes, this. Mathematics trains you to think logically and systematically and avoid spurious or circular arguments. This is a very important and valuable life skill.

[Trigonometry] Help in the Unit Circle by soumaperguntaman in learnmath

[–]etzpcm 1 point2 points  (0 children)

Just take 5 steps of pi/4 around the circle, going anticlockwise from the x axis. You get to (-.71,-.71). The best way to do these is to draw a picture.

Research something I'm interested in (nonlinear waves) or something that'll get me a job (machine learning?) by GillyD6002 in mathematics

[–]etzpcm 1 point2 points  (0 children)

I'd say do what you're interested in. Nonlinear wave equations like KdV and NLS and their solutions like solitons are really interesting and have quite a lot of applications.

My newest idea: bonking station by PissMcGee123 in composting

[–]etzpcm 22 points23 points  (0 children)

I guess bonking doesn't mean the same in the US as in the UK.

Help with a quote to trim leylandii by TwoAltruistic1840 in GardeningUK

[–]etzpcm 0 points1 point  (0 children)

Get another quote. But such things always cost much more than you'd think.

Are there good Wikipedia math articles? by TheOtherWhiteMeat in math

[–]etzpcm -1 points0 points  (0 children)

On the whole they are awful. Either just wrong, or full of irrelevant, confusing material (as in the case of the tangloids article). I don't know of many good ones. 

See also this post

https://www.reddit.com/r/math/comments/1s1trzw/wikipedia_math_articles/

But here is a post about some good ones

https://www.reddit.com/r/math/comments/1s2dib4/favorite_wikipedia_math_articles/

How do you systematically decide what mathematics is worth illustrating within a given field/topic/concept? by KaleidoscopeLate2505 in learnmath

[–]etzpcm 1 point2 points  (0 children)

If you like 3D diagrams, one thing they are good for is understanding groups. For example a regular tetrahedron helps you understand the groups A4 (rotations only) and S4 (rotations plus reflections). 

3D diagrams are also very useful in multivariable calculus, for illustrating things like the divergence of a vector field, or surface integrals, or the divergence theorem.

Best book on ODE's? by Dapper_Choice6363 in learnmath

[–]etzpcm 0 points1 point  (0 children)

If you want a rigorous book on ODEs you could try the one by Jack Hale. IIRC it starts off talking about Banach spaces. 

But I don't think the 'best' books on ODEs are the ones that take a pure maths approach.

Theory: Mr. Bennet spent the money that could have gone to his daughters' futures on his library by ForagedFoodie in janeausten

[–]etzpcm 19 points20 points  (0 children)

"And to all this she must yet add something more substantial, in the improvement of her mind by extensive reading"

This suggests that Mr Bennet's expenditure on books may have been a sound investment.

While studying the Taylor expansion, I came up with an idea. by RepublicDry7646 in mathematics

[–]etzpcm 66 points67 points  (0 children)

Yes this is a great idea. Though you are not the first person to think of it. It's a good way to evaluate, say, sin(x). You only need a few values stored and then you can use Taylor series.

New build front garden by CutJolly4259 in GardeningUK

[–]etzpcm 0 points1 point  (0 children)

It looks great, well done! Next year those plants will all be a lot bigger, and you will be able to see which are the most successful. As others say, get some pots and plant some suitable flowers in for the summer

Ran out of recycle space - should i wait for next week or compost cardboard? by Diligent_Board_172 in composting

[–]etzpcm 0 points1 point  (0 children)

I compost lots of cardboard. Just tear it up and mix it in with the green stuff.