help..............步驟
sin(30°-x) cos(30°+x) = √3/2
急急.....................計數!!
2007-04-15 9:59 pm
回答 (1)
2007-04-15 10:18 pm
✔ 最佳答案
sin(30°-x) cos(30°+x) = √3/2 0.5[sin(30°-x+30°+x)+sin(30°-x-30°-x)]= √3/2
sin60°+sin(-2x)= √3
sin(2x)=- √3/2
2x=-60°+360°n
x=-30°+180°n
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070415000051KK02418