证明:(1)∵seca=1/cosa tana=sina/cosa∴sec²a/(1-tan²a)=1/cos²a/(1-sin²a/cos²a)=1/(cos²a-sin²a)=1/cos2a=sec2a∴sec2a=sec²a/(1-tan²a)(2)∵seca=1/cosa ...相关推荐 1三角函数 sec(2a)=sec^a/1-tan^a求证 三角函数 sec(2a)=sec^a/1...
Cos2A=CosA^2-SinA^2=1-2SinA^2=2CosA^2-1 tan2A=2tanA/1-tanA^2 和差化积 sin(a)+sin(b) = 2sin[(a+b)/2]cos[(a-b)/2] sin(a)-sin(b) = 2cos[(a+b)/2]sin[(a-b)/2] cos(a)+cos(b) = 2cos[(a+b)/2]cos[(a-b)/2] cos(a)-cos(b) = -2sin[(a+b)/2]s...
cot(A-B) = (cotAcotB+1)/(cotB-cotA)倍角公式 Sin2A=2SinA•CosA Cos2A=CosA^2-SinA^2=1-2SinA^2=2CosA^2-1 tan2A=2tanA/1-tanA^2 和差化积 sin(a)+sin(b) = 2sin[(a+b)/2]cos[(a-b)/2]sin(a)-sin(b) = 2cos[(a+b)/2]sin[(a-b)/2]cos(a)+cos(...
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答案解析 查看更多优质解析 解答一 举报 原式=(sinA-1/sinA)(cosA-1/cosA)(tanA-1/tanA) =[(sin^2-1)/sinA][(cos^2A-1)cosA][(tan^2A-1)tanA] =(cos^2A/sinA)(sin^2A/cosA)(2/tan2A) =2sinAcosA/tan2A =sin2A/tan2A =cos2A 解析看不懂?免费查看同类题视频解析查看解答 ...
सिद्ध कीजिए की(1+secA)/(secA)=(sin^2A)/(1-cosA) 02:47 सिद्ध कीजिए की (cotA+cosecA-1)/(cotA-cosecA+1)=(1+cosA)/(sinA) 04:16 सिद्ध कीजिए की (1+tan^2A/1+cot^2A)=(1-tanA/...
sin²a+cos²a)/cos²asin²a+2/sinacosa 注意到sin²a+cos²a=1，sinacosa=sin2a/2 则(seca+csca)²=4/sin²2a+4/sin2a 由万能公式有sin2a=2tana/(1+tan²a)=-3/5 所以(seca+csca)²=4/sin²2a+4/sin2a=40/9 ...
解该式不成立 应该是sec^2A=tan²A+1 因为tan^2A+1 =sin^2A/cos^2A+1 =sin^2A/cos^2A+cos^2A/cos^2A =(sin^2A+cos^2A)/cos^2A =1/cos^2A =(1/cosA)^2 =sec^2A.此
三道关于三角函数的题目1.若a*secA-2*tanA=1,b*secA+tanA=2,则a^2+b^2=?2.已知logtanA(cosA)=2/3(0
证明:(tanA-secA+1)/(secA-tanA+1)=(tanA+sec... tanA+secA+1)=(sinA+1-cosA)/(sinA+1+cosA)∵(1-sinA+cosA)(sinA+1-cosA)=1-(sinA-cosA)²=1-(sin²A+cos²A-2sinAcosA)=1-(1-sin2A) =sin2A而(sinA-1+cos... 找安检机,上阿里巴巴 安检机从原料,生产,加工一系列服务.找...