F6 Maths 4
2011-11-20 6:40 pm
If sin B and cos B are the roots of the equation x^2 + k = 0, then k = ?
回答 (1)
2011-11-20 6:59 pm
✔ 最佳答案
sin² B + k = 0 ..... (1)cos² B + k = 0 .....(2)(1) + (2) :sin² B + k + cos² B + k = 01 + 2k = 0k = - 1/2
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20111120000051KK00192