作业帮两题三角函数求证明...证明两边相等.求助.1. sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -12.cot (a) + csc (a) = sin(a)/ 1-cos(a)能教教我吗?谢谢!最好有过程..
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![两题三角函数求证明...证明两边相等.求助.1. sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -12.cot (a) + csc (a) = sin(a)/ 1-cos(a)能教教我吗?谢谢!最好有过程..](/uploads/image/z/12598707-3-7.jpg?t=%E4%B8%A4%E9%A2%98%E4%B8%89%E8%A7%92%E5%87%BD%E6%95%B0%E6%B1%82%E8%AF%81%E6%98%8E...%E8%AF%81%E6%98%8E%E4%B8%A4%E8%BE%B9%E7%9B%B8%E7%AD%89.%E6%B1%82%E5%8A%A9.1.+sec%28a%29+csc%28a%29+%2B+cot+%28a%29+%2F+tan%28a%29-1+%3D%5Btan+%28a%29%2F+1-cot+%28a%29%5D+-12.cot+%28a%29+%2B+csc+%28a%29+%3D+sin%28a%29%2F+1-cos%28a%29%E8%83%BD%E6%95%99%E6%95%99%E6%88%91%E5%90%97%3F%E8%B0%A2%E8%B0%A2%21%E6%9C%80%E5%A5%BD%E6%9C%89%E8%BF%87%E7%A8%8B..)
两题三角函数求证明...证明两边相等.求助.1. sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -12.cot (a) + csc (a) = sin(a)/ 1-cos(a)能教教我吗?谢谢!最好有过程..
两题三角函数求证明...证明两边相等.求助.
1. sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -1
2.cot (a) + csc (a) = sin(a)/ 1-cos(a)
能教教我吗?谢谢!最好有过程..
两题三角函数求证明...证明两边相等.求助.1. sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -12.cot (a) + csc (a) = sin(a)/ 1-cos(a)能教教我吗?谢谢!最好有过程..
1、sec(a) csc(a) + cot (a) / tan(a)-1 =[tan (a)/ 1-cot (a)] -1
<==>1/(sinacosa)+1/(tan²a-tana)=tan²a/(tan-1)-1
<==>1/(sinacosa)+cos²a/(sin²a-sinacosa)=sin²a/(sinacosa-cos²a)-1
<==>1/sinacosa=(sin²a-sinacosa+cos²a)/(sinacosa-cos²a)+cos²a/(sinacosa-sin²a)
<==>1/sinacosa=(1-sinacosa)/[cosa(sina-cosa)]-cos²a/[sina(sina-cosa)]
<==>1/sinacosa=(sina-sin²acosa-cos²acosa)/[sinacosa(sina-cosa)]
<==>sina-cosa=sina-sin²acosa-cos²acosa
<==>cosa=sin²acosa+cos²acosa
<==>1=sin²a+cos²a
以上各步可逆,证毕
2、cot (a) + csc (a) = sin(a)/ 1-cos(a)
<==>cosa/sina+1/sina=sina/(1-cosa)
<==>(cosa+1)/sina=sina/(1-cosa)
<==>sin²a=(1-cosa)(1+cosa)
<==>sin²a=1-cos²a
<==>sin²a=sin²a
以上各步可逆,证毕