證1-cosAsinBcscC=sinAcosBcscC
回答 (1)
2013-12-18 5:36 am
✔ 最佳答案
Notice that sin C csc C = 1LHS = 1 - cosA sinB cscC = sinCcscC - cosAsinBcscC
= cscC (sinC - cosAsinB)
= cscC { sin[180 - (A + B)] - cosAsinB}
= cscC [sin(A + B) - cosAsinB]
=cscC (sinAcosB + cosAsinB - cosAsinB)
=cscCsinAcosB = RHS
收錄日期: 2021-04-11 20:13:31
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131217000051KK00127