It is tempting to try to reprove Euler's famous result that ∑1/k ~2=π~2 using power series methods of the sort taught in calculus 2. This leads to ∫_0~1-1n(1-t)/t dt, the evaluation of which presents an obstacle. With two key identities the obstacle is overcome, proving the desired result. And who discovered the requisite identities? Euler! Whether he knew of this proof remains to be discovered.
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机译：试图用微积分2中所讲的幂级数方法来证明欧拉著名的结果∑1 / k〜2 =π〜2是很诱人的。这导致∫_0〜1-1n（1-t）/ t dt ，这是一个障碍。通过两个关键身份，克服了障碍，证明了预期的结果。谁发现了必要的身份？欧拉！他是否知道这个证据还有待发现。
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