cos70掳cos50掳-sin70掳cos40掳

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热心网友

sin70cos50+cos70cos40
=sin70cos50+cos70sin(90-40)
=sin70cos50+cos70sin50
=sin(70+50)
=sin120
=cos30
=（√3 ）/2

热心网友

sin70cos50+cos70cos40
=sin70cos50+cos70sin(90-40)
=sin70cos50+cos70sin50
=sin(70+50)
=sin120
=cos30
=（√3 ）/2

热心网友

sin70cos50+cos70cos40
=sin70cos50+cos70sin(90-40)
=sin70cos50+cos70sin50
=sin(70+50)
=sin120
=cos30
=（√3 ）/2

热心网友

sin70cos50+cos70cos40
=sin70cos50+cos70sin(90-40)
=sin70cos50+cos70sin50
=sin(70+50)
=sin120
=cos30
=（√3 ）/2

热心网友

sin70cos50+cos70cos40
=sin70cos50+cos70sin(90-40)
=sin70cos50+cos70sin50
=sin(70+50)
=sin120
=cos30
=（√3 ）/2