我经济基础太差了，到韩国第一学期研究生，实在跟不上，很着急，作业又算分，跪求各位好心前辈帮帮我，题里有些乱符号大家可以不用管

Now consider the following maximization problem:x1;x2

max根号下X1+X2  X2没有根号
x1 + x2小于等于M
x1大于等于 0; x2大于等于 0

(a) First show that x1 = 0 cannot be an optimal solution. (To do this, let x1 = 0 and
x2 =x2（上面一个横道)小于等于mbe an optimal solution. Then, consider x1=a ; x2=x2(上面一个横道)-a; for small a).
(b) So you can ignore the constraint x1大于等于0: Write down the Largrangian with two
constraints (x1 + x2小于等于m and x2大于等于0);using  u for the multiplier of x1+x2小于等于m
andVfor the multiplier of x2大于等于0:
(c) Find the Kuhn-Tucker …rst order condition.（这个我一直不明白，好像还跟一元多元的有关，请指教）
(d) Show that u > 0: Thus, the constraint x1 + x2 小于等于m is binding.
(e) Divide cases: (i) V > 0, (ii) V = 0: Find the condition for m under which each
case admits the solution. Is this solution a global max?
(f) Can you identify the condition for m in (e) by just solving problem 2?