# Why is this formula useful in Iron Man 3?

I watched Iron Man 3 today, and wonder what this formula is about. Is it an important topic of physics? You know, like Transformers: Dark of the Moon, as I can recall, when an answer of some formula (problem) is got, an amazing weapon is invented. But I don't see any relationship in this movie. The picture is below:

• Apart from SystemDown's already given (and most probably correct) answer, the actual answer to the question "I wonder what this formula is about. Is it an important topic of physics?" is probably just that it's random math-scribble that's supposed to look complicated. You're just not supposed to make any sense of the particular symbols (since you also don't know the whole of the Extremis formula and thus the actual context of the formula). Commented Aug 17, 2013 at 15:18
• I am just curious about what that formula stands for, and I find the wiki page. It is from a comic book. Thanks for your comment. Commented Aug 18, 2013 at 1:57

This is the Baker-Campbell-Hausdorff formula. It demonstrates the difficulty in extending exponentials beyond strictly numbers to include things like vectors. Specifically in quantum physics it describes "quantum entanglement" which is (in general) still a largely unsolved problem.

As it appears here this equation seems to be written as to explain the interaction between two opposing electrons (alpha and beta) and the spin angular momentum (J) and wave function (Psi) of a system respectively.

Tony's basically saying that if you want to explain how two different forces will act on a system when combined then first describe to what degree those forces cancel each other out and then look at the effect of the force left over.

This formula was the problem that Dr. Hansen needed to solve to fix the flaws with the Extremis virus. As you saw in the movie, many people who are subjected to the virus reject it and die violently. Dr. Hansen's attempts to solve it always failed, but she knew Tony Stark was smart enough to do it. So the whole plot of the movie was her and Killian attempting to force Tony to solve it, and thus fix the flaws of the Extremis virus.

• You mean bomb oneself uncontrollable? Commented Aug 17, 2013 at 14:20
• @eccstartup - Yes. Many of those exposed to the virus (especially at the start) couldn't control it and detonated. Commented Aug 17, 2013 at 15:11
• This is correct as seen in the scene where Happy touches the ficus plant and it then starts to burn and then explode that is Dr. Hansen's early experiments with Extremis. After Tony's one night stand with her he leaves a formula that allows her progress past that stage to being able to use it on humans. Commented May 19, 2014 at 15:24