【導(dǎo)讀】2的導(dǎo)數(shù)y′=________.4.函數(shù)y=3的導(dǎo)數(shù)y′=________.10.已知a>0,f=ax2-2x+1+ln(x+1),l是曲線y=f在點(diǎn)P處的切線.求切。11.設(shè)函數(shù)f=ex-e-x,證明:f的導(dǎo)數(shù)f′≥2;設(shè)函數(shù)f=x+ln(x-5),g=ln(x-1),解不等式f′>g′.?!嗲悬c(diǎn)P的坐標(biāo)為(0,1),l的斜率為-1,11.證明f′=′=ex+e-x,因?yàn)閑x>0,e-x>0,所以ex+e-x≥2ex·e-x=2,所以由f′>g′,得1+1x-5>1x-1,由導(dǎo)數(shù)公式表可得sx′=-12x-12,xt′=-18t.它表示當(dāng)t=715s時(shí),梯子上端下滑的速度為m/s.