Source: 2016 Nigerian Senior MO Round 2
Tags: algebra, Inequality, inequalities
16.11.2022 12:55
Given that a,b,c,d∈R, prove that (ab+cd)2≤(a2+c2)(b2+d2).
16.11.2022 13:20
Well, just RHS−LHS=(ad−bc)2≥0...
16.11.2022 13:25
Yeah, it was just too trivial!