(2)(uv=u'v+uv 证:设f(x)=1(x)(x),则有 f(x)=lim f(+h)-f(x) lim x+h)v(x+h)-u(xv(x) h→>0 h h→>0 h lim/u(x+h)-ulv(x+h)+u(rv(x+h)-v(x h l(x)v(x)+l(x)y(x)故结论成立 推论:1)(Cu)=Clr’(C为常数) 2)(uvw)=u'vw+uv'w+uvw nx 3)(loga x) na XIna 学 HIGH EDUCATION PRESS ◎令08 机动目录上贞下臾返回结束(2) (uv) u v u v 证: 设 f (x) u(x)v(x) , 则有 h f x h f x f x h ( ) ( ) ( ) lim 0 h u x h v x h u x v x h ( ) ( ) ( ) ( ) lim 0 u (x)v(x) u(x)v (x) 故结论成立. h u x h h ( ) lim 0 u(x) v(x h) h v(x) u(x) v(x h) 推论: 1) (Cu ) 2) (uvw) Cu u vw uv w uvw 3) (loga x ) a x ln ln x ln a 1 机动 目录 上页 下页 返回 结束 ( C为常数 )