Tính nhanh 4/2.4 + 4/4.6 + 4/6.8 + ... + 4/ 2008. 2010
Giải thích
Đặt A=42.4+44.6+46.8+...+42008.2010
=2.22.4+24.6+26.8+...+22008.2010=2.12−14+14−16+16−18+...+12008−12010=2.12−12010=1−11005=10041005
Vậy A=10041005
Đặt A=42.4+44.6+46.8+...+42008.2010
=2.22.4+24.6+26.8+...+22008.2010=2.12−14+14−16+16−18+...+12008−12010=2.12−12010=1−11005=10041005
Vậy A=10041005