Question

高三数学难题求教。

若函数f(x)=x+√(13-2tx)(t∈N*)的最大值是正整数M,则M=（ ）

Answer 1

let u = √(13-2tx), then x = (13-u^2)/(2t)
f(x) = (13-u^2)/(2t)+u <= f(t)=13/(2t)+t/2=M
M是正整数,所以t=13, M=7