高校问答歌曲老街教唱:两道数学题~
来源：百度文库 编辑：高校问答 时间：2024/05/12 09:47:40
已知(sin^2A)/(sin^2B)+cos^2A*cos^2C=1
求证：tan^2A*cot^2B=sin^2c
已知：tan^2A=2tan^2B+1
求证：sin^2B=2sin^2A-1
给个清楚点的过程 3Q～
求证：tan^2A*cot^2B=sin^2c
已知：tan^2A=2tan^2B+1
求证：sin^2B=2sin^2A-1
给个清楚点的过程 3Q～
已知(sin^2A)/(sin^2B)+cos^2A*cos^2C=1
求证：tan^2A*cot^2B=sin^2c
.(sin^2A)/(sin^2B)+cos^2A·cos^2C=1
(tan^2A)/(sin^2B)+cos^2C=1/(cos^2A)=1+tan^2A
1-cos^2C=tan^2A*(1/sin^2B-1)=tan^2A*cos^2B/sin^2B
tan^2A·cot^2B=sin^2C
已知：tan^2A=2tan^2B+1
求证：sin^2B=2sin^2A-1
sin^2A/cos^2A=2sin^2B/cos^2B+1=(1+sin^2B)/cos^2B
sin^2A*cos^2B=cos^2A*(1+sin^2B)
sin^2B=2sin^2A-1
前面没有什么条件吗?A,B,C的关系?