寄件者: Mathematics@CUHK

寄件日期: 2017年11月8日 23:16

收件者: yiuyu4@hotmail.com

主旨: [New post] Euler’s formula e^ix = cos x + i sin x – a geometric approach

KKK posted: ” Today I mentioned the famous Euler’s formula briefly in my Calculus class: where is a”

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寄件者: Mathematics@CUHK

寄件日期: 2017年5月20日 15:24

收件者: yiuyu4@hotmail.com

主旨: [New post] The Cauchy-Schwarz inequality and the Lagrange identity

KKK posted: ” The classical Lagrange identity is the following: $latex \displaystyle \begin{array}{rl} \displaystyle \left(\sum_{i=1}^n a_ib_i\right)^2+\sum _{1\le i<j\le n} \left(a_ib_j-a_jb_i\right)^2 =\left(\sum_{i=1}^{n}a_i^2\right)\left(\sum_{j=1}^{n}b_j^2\rig"

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寄件者: Mathematics@CUHK

寄件日期: 2015年5月23日 9:17

收件者: yiuyu4@hotmail.com

主旨: [New post] Toric perspective 1

Hon Leung posted: “This series of posts will be about toric varieties. The author is not sure if there is a part 2, but he still calls this part 1. This post is about computing the dimensions and degrees of popular toric varieties. Readers are assumed to know linear algebra”

]]>[Nice! Thank you. -KKK]

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This function is easily seen to be weakly differentiable, and the weak derivative is zero for and . ]]>