在解题中,经常碰到求解多变元代数式的最值或取值范围问题.其中有一类问题可以对题中的变量进行双换元,从而可以达到非常有效地解决问题的目的.一、根式之和的代数式问题例1(2015年重庆高考题)设a>0,b>0,a+b=5,则(a+1)~(1/2)+(b+3)~(1/2)的最大值为 In the problem solving, often encountered in solving the multivariable algebraic equation of the most value or range of values.Among them there is a class of problems on the variables in the double swap, so as to achieve a very effective solution to the problem.First, (A + 1) ~ (1/2) + (b + 3) ~ (a + b) = 0, a + b = 5 1/2) is the maximum