solve using accumulation and $2$nd FTOC

Find $\frac{dy}{dx}$ for all of the following.

$6.$

$y={\displaystyle \underset{-}{\overset{x}{}}}\frac{2-sint}{3+cost}dt$

$y={\displaystyle \underset{x}{\overset{7}{}}}\sqrt[\phantom{2}]{2m^4+m+1}dm$

$y={\displaystyle \underset{x^3}{\overset{5}{}}}\frac{cost}{t^2+1}dt$

$y={\displaystyle \underset{\sqrt[\phantom{2}]{x}}{\overset{x^3}{}}}\sqrt[\phantom{2}]{u}sinudu$