AMO 2023 – Junior College (Lớp 11–12) Câu hỏi 4

Tính $\frac1{\sqrt9+\sqrt{11}}+\frac1{\sqrt{11}+\sqrt{13}}+\frac1{\sqrt{13}+\sqrt{15}}+\cdots+\frac1{\sqrt{959}+\sqrt{961}}$.