Slove the following equation for 0degree<=x<=360degrees
sinx+sin3x+sin5x=0
(Please show your steps)
Compound angle transformation
2008-03-02 10:50 pm
回答 (1)
2008-03-02 11:40 pm
✔ 最佳答案
sinx+sin3x+sin5x=0(sinx+sin5x)+sin3x=0
2sin[(5x+x)/2]cos[(5x-x)/2]+sin3x=0
2sin3xcos2x+sin3x=0
sin3x(2cos2x+1)=0
sin3x=0 or cos2x=-1/2
3x=0,180,360,540,720,900,1080 or 2x=120,240,480,600
x=0,60,120,180,240,300,360 or x=60,120,240,300
x=0,60,120,180,240,300,360
收錄日期: 2021-04-25 17:21:14
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080302000051KK01625