Hàm số \[y = x\sin x + \cos x\] có vi phân là:

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

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.-0,07

B.10.

C.1,1

D. - 0,4

A. 9.

B. -9.

C. 90.

D. -90.

A. \({\rm{d}}y = \frac{1}{4}{\rm{d}}x\).

B. \({\rm{d}}y = \frac{1}{{{x^4}}}{\rm{d}}x\).

C. \({\rm{d}}y = - \frac{1}{{{x^4}}}{\rm{d}}x\).

D. \({\rm{d}}y = {x^4}{\rm{d}}x\).

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

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