Vi phân của hàm số $f\left(x\right)=3x^2-x$ tại điểm x=2 , ứng với $△x=0,1$ là:

A. \({\rm{d}}y = \left( { - \cos x + 3\sin x} \right){\rm{d}}x\).

B. \({\rm{d}}y = \left( { - \cos x - 3\sin x} \right){\rm{d}}x\).

C. \({\rm{d}}y = \left( {\cos x + 3\sin x} \right){\rm{d}}x\).

D. \({\rm{d}}y = - \left( {\cos x + 3\sin x} \right){\rm{d}}x\).

A. .$dy=2(x-1)dx$

B.$dy=2(x-1)$

C.$dy=(x-1)dx$

D.$dy={(x-1)}^{2}dx$

A. \(dy = \left( {\cos 2x + 3{{\sin }^2}x\cos x} \right)dx\)

B. \(dy = \left( {2\cos 2x + 3{{\sin }^2}x\cos x} \right)dx\)

C. \(dy = \left( {2\cos 2x + {{\sin }^2}x\cos x} \right)dx\)

D. \(dy = \left( {\cos 2x + {{\sin }^2}x\cos x} \right)dx\)

A. \[{\rm{d}}y = \frac{{2\sqrt x }}{{4x\sqrt x {{\cos }^2}\sqrt x }}{\rm{d}}x\].

B. \[{\rm{d}}y = \frac{{\sin (2\sqrt x )}}{{4x\sqrt x {{\cos }^2}\sqrt x }}{\rm{d}}x\].

C. \[{\rm{d}}y = \frac{{2\sqrt x - \sin (2\sqrt x )}}{{4x\sqrt x {{\cos }^2}\sqrt x }}{\rm{d}}x\].

D. \[{\rm{d}}y = - \frac{{2\sqrt x - \sin (2\sqrt x )}}{{4x\sqrt x {{\cos }^2}\sqrt x }}{\rm{d}}x\].

A. \(dy = (1 + {\tan ^2}2x)dx\)

B. \(dy = (1 - {\tan ^2}2x)dx\)

C. \(dy = 2(1 - {\tan ^2}2x)dx\)

D. \(dy = 2(1 + {\tan ^2}2x)dx\)

A. \(dy = \frac{1}{{\sqrt[3]{{{{(x + 1)}^2}}}}}dx\)

B. \(dy = \frac{3}{{\sqrt[3]{{{{(x + 1)}^2}}}}}dx\)

C. \(dy = \frac{2}{{\sqrt[3]{{{{(x + 1)}^2}}}}}dx\)

D. \(dy = \frac{1}{{3\sqrt[3]{{{{(x + 1)}^2}}}}}dx\)