sum of products的用法和樣例：
例句
- In this paper,summation formulas of products involving odd-even index chebyshev polynomials of the second are given by using primary methods.
利用初等方法給出了一類(lèi)包含奇下標第二類(lèi)契貝謝夫多項式乘積和與一類(lèi)包含偶下標第二類(lèi)契貝謝夫多項式乘積和的求和公式。 - In this peper necessary and sufficient conditions for the semidirect products and wreath products of two scmigroup are given.
給出了兩個(gè)半群的半直積和圈積為左群的充分必要條件以及半直積的結構。
