Since 
is strictly increasing on (1, 2), therefore > 0 for all 
in (1, 2)
On (1, 2) 
Minimum value of 
is 
and maximum value is 
Since > 0 for all in (1, 2)
and 
and 
Therefore least value of 
is 
Find the least value of a such that the function f given by f(x)=x^2+ax+1 strictly increasing on (1, 2).
Find the least value of a such that the function f given by f(x)=x^2+ax+1 strictly increasing on (1, 2).