（Ⅰ）y′= 2 3 ×3x2+ 1 xln2 =2x2+ 1 xln2 ．（Ⅱ）y′=tan2x+x( sinx cosx )′=tan2x+x? 2cos2xcos2x?sin2x(?2sin2x) cos22x =tan2x+x? 2(sin22x+cos22x) cos22x =tan2x+ 2x cos22x ．
