史上最難數學題,自認高手請進(22分或以上)

Question

圖片參考：http://imgcld.yimg.com/8/n/HA00145646/o/7011100700...

請解釋圖1步驟用左咩formula. 以及解釋圖2 step6點去step7

thanks

圖片參考：http://imgcld.yimg.com/8/n/HA00145646/o/7011100700...

Update:

可唔可以prove下你所指出既rules?

Answer 1

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圖一:

用左sin(A+B)=sinAcosB+sinBcosA

&sin2A=2sinAcosA

&cos2A=1-2(sinA)^2

&(sinA)^2+(cosA)^2=1

圖二:

第五步到第六步:

4d^2*(sinθ)^2/(sin2θ)^2 * (1-(sinθ)^2) remarks: (sinθ)^2+(cosθ)^2=1

=4d^2(sinθ)^2/(sin2θ)^2 * (cosθ)^2

第六步到第七步

4d^2*(sinθ)^2*(cosθ)^2/(sin2θ)^2 remarks: 2sinθcosθ=sin2θ

=4d^2*(sinθ)^2*(cosθ)^2/(2sinθcosθ)^2

唔識再寄信比我啦!!!!