Es sei y ∈ R ≥ 0 {\displaystyle {}y\in \mathbb {R} _{\geq 0}} und n ∈ N {\displaystyle {}n\in \mathbb {N} } , n ≥ 2 {\displaystyle {}n\geq 2} . Zeige, dass ( 1 + y ) n ≥ n 2 y 2 4 {\displaystyle {}(1+y)^{n}\geq {\frac {n^{2}y^{2}}{4}}} gilt.