Question:
If x >= y and y>1 the the value of expression log base x( x / y) + log base y ( y / x) can never be
a) -1
b) -0.5
c) 0
d) 1
Answer:
Expression becomes 2-(x+1/x) where x is logx base y and minimum is 2..so it can be 0 as minimum.
x/y+y/x>=2 that is why [2- (x/y+y/x)] can't be >0
It is equal to logx X - logx Y + logy Y - logy X. logx Y take 'm' ... equation would reduce to 2-m-1/m = -(root m + 1/root m)^2. So it can never be equal to 1.