f(x)=根號(8x-x^2)-根號(14x-x^2-48)
=√x(8-x)-√(x-6)(8-x)
=√(8-x)(√x-√(x-6))
定義域：6≤x≤8
√x+√(x-6)是單調(diào)增函數(shù)
√x-√(x-6)=6/(√x+√(x-6))是單調(diào)減函數(shù)
√（8-x)也是單調(diào)減函數(shù)
即原函數(shù)y是單調(diào)減函數(shù).
所以,x=6時,f(x)有最大值=√2*(√6-0)=2√3
X=8時,有最小值是=0.