Cho hàm số $y = 3{x^5} - 5{x^4} + 3x - 2$. Giải bất phương trình $y\prime \prime < 0$

A.${y^{\left( 4 \right)}} = \frac{{7.4!}}{{{{\left( {x - 3} \right)}^5}}} - \frac{{5.4!}}{{{{\left( {x - 2} \right)}^5}}}$

B. ${y^{\left( 4 \right)}} = \frac{{5.4!}}{{{{\left( {x - 3} \right)}^5}}} - \frac{{2.4!}}{{{{\left( {x - 2} \right)}^5}}}$

C. ${y^{\left( 4 \right)}} = \frac{{5.4!}}{{{{\left( {x - 2} \right)}^5}}} - \frac{{7.4!}}{{{{\left( {x - 3} \right)}^5}}}$

D. ${y^{\left( 4 \right)}} = \frac{7}{{{{\left( {x - 3} \right)}^4}}} - \frac{5}{{{{\left( {x - 2} \right)}^4}}}$

A.$12\,m/{s^2}$

B. $8\,m/{s^2}$

C. $7\,m/{s^2}$

D. $6\,m/{s^2}$

A.$y' = \sin \left( {x + \frac{\pi }{2}} \right)$

B. $y'' = \sin \left( {x + \pi } \right)$

C. $y''' = \sin \left( {x + \frac{{3\pi }}{2}} \right)$

D. ${y^{\left( 4 \right)}} = \sin \left( {2\pi - x} \right)$

A.−cosx 

B.sinx 

C.−sinx 

D.cosx 

A.$dy = {\left( {{x^2} + 2x} \right)^\prime }dx$

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

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

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

A.$y''' = 12x\left( {{x^2} + 1} \right)$

B. $y''' = 24x\left( {{x^2} + 1} \right)$

C. $y''' = 24x\left( {5{x^2} + 3} \right)$

D. $y''' = - 12x\left( {{x^2} + 1} \right)$

A.$y'' = - \frac{{2\sin x}}{{{{\cos }^3}x}}$

B. $y'' = \frac{1}{{{{\cos }^2}x}}$

C. $y'' = - \frac{1}{{{{\cos }^2}x}}$

D. $y'' = \frac{{2\sin x}}{{{{\cos }^3}x}}$