x=0到360度
sin^2 x + 2sinx cosx = 3cos^2 x
中4數學題
2007-11-25 11:21 pm
回答 (1)
2007-11-25 11:28 pm
✔ 最佳答案
sin^2 x + 2sinx cosx = 3cos^2 xsin^2 x + 2sinx cosx - 3cos^2 x = 0
(sinx - cosx)(sinx + 3cosx) = 0
sinx = cos x or sinx = -3cosx
tanx = 1 or -3
x = 45, 225, 108.43, 288.43
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071125000051KK02680