Find x, give you answer in the interval from -180 to 180.
3sinx=4sin³x
1 trigonometry Q.
2011-08-06 9:17 pm
回答 (1)
2011-08-07 2:33 am
✔ 最佳答案
Find x，give you answer in the interval from －180degree to 180degree.3Sinx=4Sin^3 x
Sol
3Sinx=4Sin^3 x
4Sin^3 x－3Sinx=0
Sinx(4Sin^2 x－3)=0
Sinx=0 or Sin^2 x=3/4
Sinx=0 or Sinx=√3/2 or Sinx=－√3/2
x=－180度 or x=0度 or x=180度or x=60度 or x=120度
orx=－60度or x=－120度
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