请教sin(a+b)-sina=2cos(a+b/2)sinb/2sin(a+b)-sina=2cos(a+b/2)sinb/2如何化解的?这是在求导数b趋近于0时碰到的,但是好像是直接化解的,还没用到极限去化解

请教sin(a+b)-sina=2cos(a+b/2)sinb/2sin(a+b)-sina=2cos(a+b/2)sinb/2如何化解的?这是在求导数b趋近于0时碰到的,但是好像是直接化解的,还没用到极限去化解
请教sin(a+b)-sina=2cos(a+b/2)sinb/2
sin(a+b)-sina=2cos(a+b/2)sinb/2
如何化解的?
这是在求导数b趋近于0时碰到的,但是好像是直接化解的,还没用到极限去化解

请教sin(a+b)-sina=2cos(a+b/2)sinb/2sin(a+b)-sina=2cos(a+b/2)sinb/2如何化解的?这是在求导数b趋近于0时碰到的,但是好像是直接化解的,还没用到极限去化解
这个是和差化积公式,
当然可以用两角和和差的正弦公式展开得到
sin(a+b)=sin(a+b/2+b/2)=sin(a+b/2)cos(b/2)+cos(a+b/2)sin(b/2)
sina=sin(a+b/2-b/2)=sin(a+b/2)cos(b/2)-cos(a+b/2)sin(b/2)
上面两式相减得到
sin(a+b)-sina=2cos(a+b/2)sin(b/2)

用和差化积公式

ain(a+b)-sinb=2cos[（a+b)/2+a/2]sin[(a+b)/2-a/2]=2cos(a+b/2)sinb/2

Comments WikiLeaks and Julian Assange

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Given the broad spectrum of organizations, it's not easy to identify the common denominator. The quote above may give a partial answer. All of these organizations are "institutional hierarchies" and "patronage networks".
Wednesday, 16 June 2010 WikiLeaks and Julian Assange
A scan of the titles of leaked documents shows that WikiLeaks's targets are not just governments and corporations, although as generators of mountains of documents, it's hardly surprising that they feature prominently. Other organizations include FARC (a Colombian Marxist guerrilla force), the British National Party and other fascist outfits, the United Nations, the Church of Scientology (and other religious cults), and the Newfoundland Masonic Lodge.??
Take some time to read Khatchadourian's article. Although it's long, it explains what WikiLeaks is all about, and the way it operates. Khatchadourian also provides a fascinating profile of the enigmatic Julian Assange, one of WikiLeak's founders and its public face:
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Given the broad spectrum of organizations, it's not easy to identify the common denominator. The quote above may give a partial answer. All of these organizations are "institutional hierarchies" and "patronage networks".

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The Strategist A journal on global affairs, ideas and influences
A scan of the titles of leaked documents shows that WikiLeaks's targets are not just governments and corporations, although as generators of mountains of documents, it's hardly surprising that they feature prominently. Other organizations include FARC (a Colombian Marxist guerrilla force), the British National Party and other fascist outfits, the United Nations, the Church of Scientology (and other religious cults), and the Newfoundland Masonic Lodge.??
Take some time to read Khatchadourian's article. Although it's long, it explains what WikiLeaks is all about, and the way it operates. Khatchadourian also provides a fascinating profile of the enigmatic Julian Assange,chanel store, one of WikiLeak's founders and its public face:
Wikileaks is running an open source insurgency against nation-state and corporate security systems.
This New Yorker article, by Raffi Khatchadourian, describes WikiLeaks as a "populist intelligence network". I like John Robb's description better:
He had come to understand the defining human struggle not as left versus right, or faith versus reason, but as individual versus institution. As a student of Kafka, Koestler,omega seamaster, and Solzhenitsyn, he believed that truth, creativity, love, and compassion are corrupted by institutional hierarchies, and by “patronage networks”—one of his favorite expressions—that contort the human spirit.
He had come to understand the defining human struggle not as left versus right,omega seamaster, or faith versus reason,mbt shop, but as individual versus institution. As a student of Kafka, Koestler, and Solzhenitsyn, he believed that truth, creativity,mbtshoes, love, and compassion are corrupted by institutional hierarchies, and by “patronage networks”—one of his favorite expressions—that contort the human spirit.
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Wikileaks is running an open source insurgency against nation-state and corporate security systems.
This New Yorker article, by Raffi Khatchadourian, describes WikiLeaks as a "populist intelligence network". I like John Robb's description better:

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