作业帮函数最值
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/06 01:41:36
函数最值
函数最值
函数最值
解f(x)=1/4[1/x+36/(5-x)]
=1/4[1/x+36/(5-x)]×1
=1/4[1/x+36/(5-x)]×[x+(5-x)]/5
=1/20[1/x+36/(5-x)]×[x+(5-x)]
=1/20[1+36+(5-x)/x+36x/(5-x)]
=1/20[37+(5-x)/x+36x/(5-x)]
=37/20+1/20[(5-x)/x+36x/(5-x)]
≥37/20+1/20×2√(5-x)/x×36x/(5-x)
=37/20+12/20
=49/20
故函数的最小值为49/20。