One way to stop TR is to flinch the TR-setter (if possible). One way to do this is to go for a Move like Rock Slide, which has 90% Accuracy and a 30% flinch chance. It's possible for both of your Pokémon to go for it at the same time to increase your chances of getting the flinch.
What are the odds of getting a flinch on the TR-setter if you go for double-Rock Slide, factoring in the miss chance...and what is the equation?
I did this:
(n.b. Chance to flinch expressed as a decimal, as 0,3; chance to miss expressed as a decimal, as 0,9))
(1+0,3)(1+0,3)-1=1,69-1=0,69x0,9x,09=0,5589
The reason I add a 1 to the flinch chance and then take it out is because it will compound the odds in a positive direction; without doing this, the odds would decrease because you're taking a third of a third. I think it makes sense to take the 1 back out as soon as you are done modifying the flinch chance, though (as opposed to pretending like its not there for the rest of the equation and ignoring it when looking at the percentage at the end)
Edit: thank you to
Yellow Paint for solving the problem! The equation he used was as follows:
1 - (.7 / .9)^2 = 0.39506172839506193
One crucial piece of info he gave was that if you used the chance to miss, the equation I was using would produce a decimal >1,0, which would mean it'd have >100% chance of happening, which isn't accurate at all.