y=x³-1/sinx
令u=sinx, v=1/u
则y=x³-v
y'=(x³)'-dv/dx
=3x²-(dv/du)(du/dx)
=3x²-(-1/u²)[d(sinx)/dx]
=3x²+cosx/sin²x
复合函数求Y等于X的三次方-1除以SINx的导数
y=x³-1/sinx
令u=sinx, v=1/u
则y=x³-v
y'=(x³)'-dv/dx
=3x²-(dv/du)(du/dx)
=3x²-(-1/u²)[d(sinx)/dx]
=3x²+cosx/sin²x