## Does something count as “dealing damage” if its damage is reduced to zero?

An example of a feature where this sort of thing matters is the Optional Favored Foe feature for the Ranger from Tasha’s Cauldron of Everything (emphasis mine):

[…] The first time on each of your turns that you hit the favored enemy and deal damage to it, including when you mark it, you can increase that damage by 1d4. […]

This clearly means that if you hit with an attack that never deals damage, you would not trigger Favored Foe, but what happens if you hit with an attack that can deal damage but that damage was reduced to zero by either damage reduction, resistance, immunity or some other sort of feature; have you still dealt damage?

This question is different from the following:

• Does dealing 0 damage to a concentrating spellcaster require a saving throw?

As Constitution saving throws result from a creature taking damage, not from a creature dealing damage.

## Step size is effectively zero; singularity or stiff system suspected

\[Eta] = 0.125; rg1s = Derivative[1][u1][t] - u1[t]*u3[t] - 3*u1[t]*u4[t] + u2[t]*u3[t] + 3*u2[t]*u4[t] + 2*(1 + 2*\[Eta])*u1[t]^2 == 0; rg2s = Derivative[1][u2][t] - u2[t]*u3[t] - 3*u2[t]*u4[t] + u1[t]*u3[t] + 3*u1[t]*u4[t] + 2*(1 + 2*\[Eta])*u2[t]^2 == 0; rg3t = Derivative[1][u3][t] - 0.5*((u1[t] - u2[t])^2 + u3[t]^2 - 3*u4[t]^2 + 6*u3[t]*u4[t]) == 0; rg4t = Derivative[1][u4][t] - 0.5*((u1[t] - u2[t])^2 + u3[t]^2 + 5*u4[t]^2 - 2*u3[t]*u4[t]) == 0; sol = NDSolve[{rg1s, rg2s, rg3t, rg4t, u1[0] == -0.6*0.2, u2[0] == -0.6*0.2, u3[0] == 0.6*0.2, u4[0] == 0.2}, {u1, u2, u3, u4}, {t, 1, 10}]I am trying to solve four coupled nonlinear differential equations. But, everytime I am getting NDSolve::ndsz: At t == 2.0833315360868916, step size is effectively zero; singularity or stiff system suspected. I have tried all the possible ways to solve such kind of problem with similar kind of problems available in stack. I want to get the value of g1,g2,g3 and g4 for large value of t i.e. 1 to 100 but I am getting only for small value of t? Could you please suggest me some way to sort out the issue?

Thank you

## How do I use Any Dice to calculate Mutant Year Zero d66 odds?

In Mutant Year Zero, Alien RPG and Forbidden Lands, the designers include a lot of d66 tables, in which a d6 is rolled for the tens and one for the units, giving 36 possible results (11, 12, 13, 14, 15, 16, 21, 22, etc). How would I be able to simulate this in Any Dice?

## How to find lines of matrix that has the property of being zero everywhere except for 1 entry?

I am interested in finding the lines where all entries are equal to zeros except for one.

Example: Given the follwoing matrix:

$$\begin{bmatrix}0 &0 &3 & 8\ 0 & 4 & 0 & 0 \ 0 &1 & 0 & 1\end{bmatrix}$$

Only the second line verify this property.

Of course, the brute force way is to go over the entries and check them one by one. But I am wondering if there is another most efficient way I don’t know about.