Hi.
I have been wondering how to show that two variables function is greater than zero. I thought about calculating minima and from Intermediate value theorem showing that it isn't negative. So how can I calculate
lim(x,y)-> (∞, ∞) f(x,y) , lim(x,y)-> (∞,-∞) f(x,y), lim(x,y)-> (-∞,-∞) f(x,y) and lim(x,y)-> (-∞,∞) f(x,y)?
sometimes it's easy but i don't know what to do with something like this 4a2 + 4a - 2ab + b2 +2 > 0
I have been wondering how to show that two variables function is greater than zero. I thought about calculating minima and from Intermediate value theorem showing that it isn't negative. So how can I calculate
lim(x,y)-> (∞, ∞) f(x,y) , lim(x,y)-> (∞,-∞) f(x,y), lim(x,y)-> (-∞,-∞) f(x,y) and lim(x,y)-> (-∞,∞) f(x,y)?
sometimes it's easy but i don't know what to do with something like this 4a2 + 4a - 2ab + b2 +2 > 0