3=sqrt(9)=sqrt(1+2×4)=sqrt(1+2×sqrt(16))=sqrt(1+2×sqrt(1+3×5))=sqrt(1+2×sqrt(1+3×sqrt(25)))=sqrt(1+2×sqrt(1+3×sqrt(1+24)))=sqrt(1+2×sqrt(1+3×sqrt(1+4×6)))=sqrt(1+2×sqrt(1+3×sqrt(1+4×sqrt(36))))=...=sqrt(1+2×sqrt(1+3×sqrt(1+4×sqrt(...)))) 처럼 생각하면 답은 3입니다!