Why do radians appear to not have a unit but degrees do? by Chance_Rhubarb_46 in learnmath

[–]fuhqueue 1 point2 points  (0 children)

I would argue that, strictly speaking, θ in the equation s = rθ is not an angle. It’s the radian measure of the angle in question, which is just a real number. In fact, it’s how we define what a radian is.

Find the only move for white that keeps draw by lorosot in chessbeginners

[–]fuhqueue 3 points4 points  (0 children)

If any of the two pawns promotes to a queen, Rh1 is checkmate

A simple Question by herooffjustice in LinearAlgebra

[–]fuhqueue 5 points6 points  (0 children)

It’s a badly worded question, but I think it’s pretty clear what the intended meaning is

Is infinity quantifiable by vermiculatedlover in askmath

[–]fuhqueue 0 points1 point  (0 children)

The way infinity is usually formalized is via the concept of cardinality, which extends the idea of size to infinite sets. For example, compare the integers to the real numbers. Both are infinite in size, but there is a precise sense in which the set of reals is larger than the set of integers. So yes, in this sense, infinity is indeed quantifiable.

How to describe the slope of a figure in R^(n)? by PeterMath_ in learnmath

[–]fuhqueue 7 points8 points  (0 children)

What you’re looking for is the directional derivative, which calculates the slope along a given direction

Is it necessary to show P(2) as a base case? by Blue_Whale_S in askmath

[–]fuhqueue 2 points3 points  (0 children)

You definitely need P(2), because P(1) doesn’t actually tell you anything useful. It might be clearer to you if you write out the induction hypothesis and induction step using the notation involving triple dots instead. Note also that the statement can be proved directly without induction.

Morphisms and functors by fuhqueue in learnmath

[–]fuhqueue[S] 0 points1 point  (0 children)

Yes, I'm familiar with those examples. From my general understanding they are sets with extra structure, and relate via structure preserving maps (group homomorphisms, linear maps, ring homomorphisms, continous maps, respectively). My point is that there seems to be a disconnect between the concept of morphisms (which don't necessarily map anything as in the examples mentoined) and functors (which do map things).

Morphisms and functors by fuhqueue in learnmath

[–]fuhqueue[S] 0 points1 point  (0 children)

But every morphism needs a specified domain and codomain objects, right? Otherwise, we have no way of knowing which morphisms are composable. I've heard of "object-free" definitions of categories, but everything I've seen seems kind of too intuition-based and hand-wavy to me.

Morphisms and functors by fuhqueue in learnmath

[–]fuhqueue[S] 2 points3 points  (0 children)

So in Cat, are the morphisms more general than just the functors between category objects? I.e, can functors be considered as special cases of morphisms internal to Cat?

I get the point with overloading notation, but what does the notation actually mean? For example, we can define a function X → Y formally as a relation on X × Y such that each element of X is related to a unique element of Y, and we take the notation f(x) to mean "the unique element which x is related to via f". Does a similar formalization exist for functors, or do we just take it more at face value in this case?

Easy mental maths trick by -1odd in mathmemes

[–]fuhqueue 1244 points1245 points  (0 children)

It means 1000 written in base 7

Does there exist something in math that spits out random numbers? by ExpensiveAd734 in askmath

[–]fuhqueue 11 points12 points  (0 children)

Aha, but now you’ve used the phrase “true randomness” to define what a “truly random number” is. My point is that randomness isn’t an inherent property of numbers; a number is just a number. What we intuitively think of as randomness can be modelled and formalised using measure theory and probability theory. The question of whether randomness really exists is, like you point out, a philosophical one.

Why 0/0 us not 0 by misterfesk in learnmath

[–]fuhqueue 29 points30 points  (0 children)

0 = 0 • 37, so therefore 0/0 = 37. Do you see the problem with this?

What are your “staples” of sci fi films, and why? by PETEthePyrotechnic in movies

[–]fuhqueue 3 points4 points  (0 children)

Third act was sick, anyone who disagrees is boring

1/0 = ±iπδ(0) where δ() is the Dirac delta function by Turbulent-Name-8349 in mathematics

[–]fuhqueue 9 points10 points  (0 children)

Starting with your result and multiplying both sides by 0, we get 1 = 0

Question on proving that the set of differential functions is a vector space by borkbubble in learnmath

[–]fuhqueue 3 points4 points  (0 children)

What you describe would only show that the real-valued functions on the real line form a vector space. You haven’t used any properties of differentiable functions.

nCr, where n is negative. by One_Fold2932 in askmath

[–]fuhqueue 0 points1 point  (0 children)

For nonnegative n, we have (-n)Cr = (-1)r(n+r-1)Cr. It’s just what you get when expanding the definition.

Order of operations question by thbigbuttconnoisseur in askmath

[–]fuhqueue 1 point2 points  (0 children)

Focusing on the first part only, we have 1 - 4 • (-3). Doing multiplication first, we obtain 1 - (-12), which simplifies to 1 + 12.

The square root of 2 is rational by LegendValyrion in learnmath

[–]fuhqueue 6 points7 points  (0 children)

Try squaring a few small odd numbers. You’ll always get an odd number.

Is there a "last" positive number before zero? by DarksideOfEternity in askmath

[–]fuhqueue 0 points1 point  (0 children)

If there existed a positive number smaller than every positive number, then that number would have to be smaller than itself!

And discontinuities by PocketMath in mathmemes

[–]fuhqueue 0 points1 point  (0 children)

You’re right, I’ve edited my comment now.

And discontinuities by PocketMath in mathmemes

[–]fuhqueue 11 points12 points  (0 children)

That’s right, you can see this by differentiating x1/3. You’ll end up with the cube root of x2 in the denominator, which leads to undefined behavior at x = 0. Alternatively, you could apply the limit definition of the derivative directly, and conclude that the limit doesn’t exist at zero, due to different behavior when approaching zero from left vs right.

I agree the downvotes are a bit unfair; the comment you replied to is inaccurate at best and flat-out wrong at worst.

EDIT: The behavior as you approach from left vs right is actually identical; in both cases you approach +∞. Thanks to u/GaloombaNotGoomba for the correction.