F.4 A.maths歸約公式 help me!!!!!!
回答 (2)
2009-10-04 7:54 pm
✔ 最佳答案
By using formula:cos(A-B)=cosAcosB+sinAsinB
Sub A=nx and B=x, we have:
cos(nx-x)=cosnxcosx+sinnxsinx
cos(n-1)x=cosnxcosx+sinnxsinx
sinnxsinx=cos(n-1)x-cosnxcosx
2009-10-04 10:42 pm
formula: cos(A-B)=cosAcosB+sinAsinB
Let nx=A, x=B
cos(nx-x) = cosnx cosx- sinnx sinx
cos(n-1)x = cosx cos(nx)- sin(nx)sinx
sin(nx)sinx= cos(n-1)x-cosx cos(nx)
Let nx=A, x=B
cos(nx-x) = cosnx cosx- sinnx sinx
cos(n-1)x = cosx cos(nx)- sin(nx)sinx
sin(nx)sinx= cos(n-1)x-cosx cos(nx)
參考: me
收錄日期: 2021-04-22 00:45:46
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https://hk.answers.yahoo.com/question/index?qid=20091004000051KK02419