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最讨厌提问者写式子时不加括号＝＝＝＝＝＝
x+[4/(x+1)]
=(x+1)+[4/(x+1)]-1
≥2√[(x+1)*4/(x+1)]-1
=2√4-1
=3
当x+1=4/(x+1)，(x+1)²=4，x=1时，不等式取等号
即当x=1时，式子x+[4/(x+1)]取最小值3
x+4/x+1=1+3/(x+1)>3
没有最小值
x+[4/(x+1)]
=(x+1)+[4/(x+1)]-1
≥2√[(x+1)*4/(x+1)]-1
=2√4-1
=3
当x+1=4/(x+1)，(x+1)²=4，x=1时，不等式取等号
即当x=1时，式子x+[4/(x+1)]取最小值3
已知x>-1求x取何值时，(x+4)/(x+1)的最小值 记得加括号啊
x+[4/(x+1)]
=(x+1)+[4/(x+1)]-1
≥2√[(x+1)*4/(x+1)]-1
=2√4-1
=3
当x+1=4/(x+1)，(x+1)²=4，x=1时，不等式取等号
即当x=1时，式子x+[4/(x+1)]取最小值3
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