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理科第（２０）题解法１：设Ａ＋Ｃ＝α，又Ａ－Ｃ＝π３，得Ａ＝α２＋π６，Ｃ＝α２－π６，∵ａ＋ｃ＝２ｂ，由正弦定理，得ｓｉｎＡ＋ｓｉｎＣ＝２ｓｉｎＢ＝２ｓｉｎ（Ａ＋Ｃ）．２ｓｉｎα２ｃｏｓπ６＝２ｓｉｎαｃｏｓα２＝３４．∴ｓｉｎＢ＝ｓｉｎ（Ａ＋Ｃ...
Science (20) Problem Solving Method 1: Let A+C=α, and A-C=π3, get A=α2+π6, C=α2-π6, ∵a+c=2b, from sine theorem, get sinA+sinC=2sinB=2sin(A+C) . 2sinα2cosπ6=2sinαcosα2=34. ∴sinB=sin(A+C...