Which type of questions do we use
Arithmetic mean >=Geometric mean euation.

Hi
The questions involving maximum and minimum values of terms are the questions where we use Arithmetic mean >= Geometric mean.
For example of a question says a+b=12 and a and b are real numbers and find the maximum value of ab
so we will use AM>=GM
Which means (a+b)/2 >= (ab)^1/2
so we get 6>= (ab)^1/2
squaring both sides
we get
36>= ab
Hence ab is less than equal to 36 or maximum value of ab will be 36.