設a,b,c∈正實數,a+b+c=7,則√a+√b+√c的最大值為

設a,b,c∈正實數,a+b+c=7,則√a+√b+√c的最大值為

(√a+√b+√c)^2=a+b+c+2√ab+2√bc+2√ac=7+2√ab+2√bc+2√ac