1、1ysinx(1cosx)的导数是()Acosxcos2xBcosxcos2xCsinxcos2x Dcos2xcos2x答案B解析y(sinx)(1cosx)sinx(1cosx)cosx(1cosx)sinxsinxcosxcos2xsin2xcosxcos2x.2曲线f(x)x3x2在点P0的切线平行于直线y4x1,则P0的坐标为()A(1,0) B(2,8)C(1,0)和(1,4) D(2,8)和(1,4)答案C解析f(x)3x21在点P0处的导数为f(x0)3x01,3x014,x01.P(1,0)和P(1,4)应选C.3(2010江西卷)若函数f(x)ax4bx2c满足f(1)2,
2、则f(1)()A1 B2C2 D0答案B解析由f(x)ax4bx2c,得f(x)4ax32bx.又f(1)2,所以4a2b2,即2ab1,f(1)4a2b2(2ab)2.故选B.4已知f(x)3x26x,且f(0)4,解不等式f(x)0.解析f(x)3x26x,可设f(x)x33x2c.又f(0)4,c4.不等式f(x)0即为x33x240,即(x1)(x2)20,x1且x2.原不等式解集为x|x1且x25求下列函数的导数(1)yx43x25x6;(2)yxtanx;(3)y(x1)(x2)(x3);(4)y.解析(1)y4x36x5.(2)ytanxx()tanxxtanxxsec2x.(3)y(x2)(x3)(x1)(x2x3)x25x62x27x53x212x11.(4)y1,y.