show that x^2 - 4xy + 5y^2 >= 0 for all real values of x and y.
to do this must i simply prove that the quardatic has no real roots? does the absence of real roots always prove that all values of the given variable fulfill the conditions?
show that x^2 - 4xy + 5y^2 >= 0 for all real values of x and y.
to do this must i simply prove that the quardatic has no real roots? does the absence of real roots always prove that all values of the given variable fulfill the conditions?