已知sin (π/6-x) =3/5,则cos(x+π/3)三角函数快忘完了。

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已知sin (π/6-x) =3/5,则cos(x+π/3)三角函数快忘完了。
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已知sin (π/6-x) =3/5,则cos(x+π/3)三角函数快忘完了。
已知sin (π/6-x) =3/5,则cos(x+π/3)
三角函数快忘完了。

已知sin (π/6-x) =3/5,则cos(x+π/3)三角函数快忘完了。
cos(x π/3)=cos(π/2-(-x π/6))=sin (π/6-x) =3/5

记A=π/6-x,B=X+π/3===>A+B=π/2===>COS(X+π/3)=COSB=COS(π/2-A)=SINA=3/5

sin (π/6 - x) = 3/5
π/6 - x = arcsin 0.6
x = π/6 - arcsin 0.6
cos (x + π/3)
= cos (π/6 - arcsin 0.6 + 60)
= cos (30 - arcsin 0.6 + 60)
= cos (90 - arc sin 0.6)
三角函数,
co...

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sin (π/6 - x) = 3/5
π/6 - x = arcsin 0.6
x = π/6 - arcsin 0.6
cos (x + π/3)
= cos (π/6 - arcsin 0.6 + 60)
= cos (30 - arcsin 0.6 + 60)
= cos (90 - arc sin 0.6)
三角函数,
cos (π/2 - u) = sin u
cos (90 - arc sin 0.6)
= sin (arcsin 0.6)
= 0.6
纯手打,蒙采纳,谢谢~~

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