求詳解 此微分導函數?

1
f(x)=x-(4/x)
f(x)=x-4(x^-1)
f'(x)=1-(-1)(4)(x^-2)
f'(x)=1+4(x^-2)

2
f(x)=[2-(1/x)]/(x-3)
f(x)=[2-(x^-1)][(x-3)]^-1
f'(x)=[2-(x^-1)](-1)(1)[(x-3)]^-2 +[(x-3)]^-1 [-(-1)]
f'(x)=[(x^-1)-2][(x-3)]^-2 +(x-3)^-1

3
f(x)=(sin x)/(x^3)
f(x)=(x^-3)(sin x)
f'(x)=(-3x^-4)(sin x)+(cos x)(x^-3)

4
y=3(1- sin x)/(2 cos x)
y=1.5(1-sin x)[(cos x)^-1]
dy/dx=1.5(1-sin x)(-1)[(cos x)^-2](-sin x)+1.5[(cos x)^-1](- cos x)
dy/dx=1.5(sin x)(1-sin x)(cos x^-2)-1.5