# 中国初中生集体挑战美国高考数学SAT题

[Hint]:

$(a + x)^{\frac {1}{3}} + (a - x)^{\frac {1}{3}} = 2(a)^{\frac {1}{3}} + 2(x)^{\frac {1}{3}}$

# The Legend of Question Six (IMO 1988)

This question was submitted  by West Germany to the IMO Committee, the examiners could not solve it in 6 hours.

In the IMO (1988) only 11 contestants solved it,  one of them proved it elegantly. Terence Tao (13, Australia) only got 1 mark out of 7 in this question.

Solution

# Unknown German Retiree Proved The “Gaussian Correlation Inequality” Conjecture

https://www.wired.com/2017/04/elusive-math-proof-found-almost-lost

$\boxed {P (a + b) \geq P (a) \times P (b)}$

Case “=” : if (a, b) independent
Case “>” : if (a, b) dependent

Thomas Royen used only high-school math (function, derivative) in his proof in 2014. He then published it in arxiv.org website – like Perelman did with the “Poincaré Conjecture”.

# Fun Math Without Math

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See clearer if change person to taxi car, bun to passenger.

9 taxi cars send 9 passengers will take the SAME timing as 3 taxi cars send 3 passengers.