cos^2(a+b)=?
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cos^2(a+b)=?
![cos^2(a+b)=?](/uploads/image/z/19015570-10-0.jpg?t=cos%5E2%28a%2Bb%29%3D%3F)
1/1+tan^2(a+b)=1/(cos(a+b)^2+sin(a+b)^2)/cos(a+b)^2=cos^2(a+b)
麻烦采纳,谢谢!
麻烦采纳,谢谢!
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