(1)$\int \sin^2x \cos xdx=\underline{\quad\quad\quad}$.
(2) $\int \dfrac { \cos x- \sin x}{( \sin x+ \cos x)^{2}}dx= \underline { \quad \quad \quad }$.
(3) $\int \dfrac { \sin 2x}{4+ \sin ^{4}x}dx= \underline { \quad \quad \quad }$.
(4)$\int \tan^4xdx=\underline { \quad \quad \quad }$.
(5)$\int \tan^3x\sec x dx=\underline { \quad \quad \quad }$.