need to have steps!!!
更新1:
超凡學生 : 180+(-1)n(30),where n is an integer. 咩黎?
sinθcosθ= 0.25 , θ = ?
回答 (3)
2009-06-10 12:20 am
✔ 最佳答案
sinθcosθ= 0.25 1/2sin2θ=0.25
sin2θ=0.5
2θ=180+(-1)n(30),where n is an integer.
θ=90o+(-1)n(15o)
2009-06-09 17:25:59 補充：
呢個係GENERAL SOLUTION
2009-06-09 17:30:18 補充：
2θ=180n度+(-1)^n(30度),where n is an integer.
θ=90n度+(-1)^n(15度)
2009-06-10 1:24 am
2009-06-10 1:18 am
sinθcosθ= 0.25
2x(sinθ)(cosθ)=2x0.25
sin(2θ)=0.5
(因為sin30=0.5)
正常計法:
sin(2θ)=0.5
2θ=30
θ=15
general formal:
sin(2θ)=0.5
2θ=180+(-1)n(30)
θ=90+(-1)n(15) ,where n is an integer(n係一個整數) <---即係話n代咩都岩
2x(sinθ)(cosθ)=2x0.25
sin(2θ)=0.5
(因為sin30=0.5)
正常計法:
sin(2θ)=0.5
2θ=30
θ=15
general formal:
sin(2θ)=0.5
2θ=180+(-1)n(30)
θ=90+(-1)n(15) ,where n is an integer(n係一個整數) <---即係話n代咩都岩
參考: ME
收錄日期: 2021-04-19 14:31:10
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090609000051KK00913