Suppose 3 a+3 b > =4 holds
Because 3a+3b > = 2 √ (3 AB)
Then 2 √ (3ab) > = 4,3 ab > =4, ab & gt=log3 (radix) 4, ab> 1
Because a+b= 1.
So ab < = 1/4
Assumption is not valid
So if a>0, b>0, a+b= 1, then 3 A+3 B.