19 câu Dạng 1: Tính vi phân

A. $dy=\frac{1}{2\sqrt{x^2-5x}}dx$        

B. $dy=\frac{2x-5}{\sqrt{x^2-5x}}dx$.

C. $dy=-\frac{2x-5}{2\sqrt{x^2-5x}}dx$.

D. $dy=\frac{2x-5}{2\sqrt{x^2-5x}}dx$.

A. $dy=\left(2\sin x+x\cos x\right)dx$ .

B. $dy=x\cos xdx$

C.   $dy=x\cos x$           

D. $dy=\left(\sin x+\cos x\right)dx$

A. 1,2608.

B. 1,2611.

C. 1,3391

D. 1,3392.

A. $\frac{d\left(\sin x\right)}{d\left(\cos x\right)}=-\cot x$.           

B. $\frac{d\left(\sin x\right)}{d\left(\cos x\right)}=-\tan x$.

C. $\frac{d\left(\sin x\right)}{d\left(\cos x\right)}=\cot x$.  

D. $\frac{d\left(\sin x\right)}{d\left(\cos x\right)}=\tan x$ .

A. $dy=2\left(x-1\right)dx$ .

B. $dy={\left(x-1\right)}^{2}dx$.

C. $dy=2\left(x-1\right)$. 

D. $dy=\left(x-1\right)dx$.

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

B. $dy={\left(x-1\right)}^{2}dx$.    

C. $dy=2\left(x-1\right)$.

D. $dy=\left(x-1\right)dx$ .

A. $dy=\frac{1}{\sqrt{1+x^2}}dx$.   

B. $dy=\frac{x}{\sqrt{1+x^2}}dx$.

C.$dy=\frac{2x}{\sqrt{1+x^2}}dx$      

D.$dy=\frac{1+x^2}{\sqrt{1+x^2}}dx$

A. $dy=\frac{3}{\sqrt{3x+2}}dx$ .  

B. $dy=\frac{1}{2\sqrt{3x+2}}dx$.

C. $dy=\frac{1}{\sqrt{3x+2}}dx$ .   

D. $dy=\frac{3}{2\sqrt{3x+2}}dx$.

A. $dy=-\frac{8}{{\left(2x-1\right)}^2}dx$ .          

B. $dy=\frac{4}{{\left(2x-1\right)}^2}dx$.

C. $dy=-\frac{4}{{\left(2x-1\right)}^2}dx$.           

D.$dy=-\frac{7}{{\left(2x-1\right)}^2}dx$ .

A. $dy=\left(x\cos x-\sin x\right)dx$.

B. $dy=\left(x\cos x\right)dx$ .

C. $dy=\left(\cos x-\sin x\right)dx$.

D. $dy=\left(x\sin x\right)dx$.

A. $df\left(x\right)=\frac{-\sin 4x}{2\sqrt{1+{\cos }^{2}2x}}dx$.

B. $df\left(x\right)=\frac{-\sin 4x}{\sqrt{1+{\cos }^{2}2x}}dx$ .

C. $df\left(x\right)=\frac{\cos 2x}{\sqrt{1+{\cos }^{2}2x}}dx$.

D. $df\left(x\right)=\frac{-\sin 2x}{\sqrt{1+{\cos }^{2}2x}}dx$.

A. $dy=\frac{2\sqrt{x}}{4x\sqrt{x}{\cos }^2\sqrt{x}}dx$.

B. $dy=\frac{\sin \left(2\sqrt{x}\right)}{4x\sqrt{x}{\cos }^2\sqrt{x}}dx$ .

C.$dy=\frac{2\sqrt{x}-\sin \left(2\sqrt{x}\right)}{4x\sqrt{x}{\cos }^2\sqrt{x}}dx$.

D. $dy=\frac{2\sqrt{x}-\sin \left(2\sqrt{x}\right)}{4x\sqrt{x}{\cos }^2\sqrt{x}}dx$ .

A. $dy=\frac{1}{4}dx$.

B. $dy=\frac{1}{x^4}dx$ .

C.$dy=-\frac{1}{x^4}dx$ .

D.$dy=x^{4}dx$ .