§3-、(x),g(x)满足(1)(2)则f(x),g(x)存在,且g(x)0证:由(2),f(x)和g(x)可导,故f(x)和g(x)在x=x0:若f(x)和g(x)连续,则f(x0)=g(x0)=0若f(x)和g(x)不连续,则令f(x0)=g(x0)=0设xU(x0),则在[x0,x]或[x,x0]上由Cauchy中值定理有(在x与x0之间)x0x令xx0(从而x0),:=::若f(x),g(x)仍满足定理条件,(x),g(x)满足(1)(2)当|x|>X时,f'(x)与g'(x)存在,且g'(x)0(3)则证::=1二、(x),g(x)满足(1)(2)则f(x),g(x)存在,且g(x)0(x)(x)(x)(x)(x)(当|x|>X时),:=0(>0)
第三章第三章2章节 来自淘豆网www.taodocs.com转载请标明出处.