I。 If x^4+y^4=100,then the greatest possible value of x is between 3 and 6.(请教思路)
2。F or which of the following fuctions is f(a+b)=f(a)+f(b) for all positive numbers a and b? (1) f(x)=x^2 (2) f(x)=x+1 (3)f(X)=根号向(4)f(x)=2/x (5)f(x)=-3x9请教思路
For which of the following fuctions is f(a+b)=f(a)+f(b) for all positive numbers a and b? (1) f(x)=x^2 (2) f(x)=x+1 (3)f(X)=根号向(4)f(x)=2/x (5)f(x)=-3x9请教思路