Tim ti so cua A va B ,biet rang
A=\(\frac{1}{1+1981}\)\(+\frac{1}{2+1982}+...+\frac{1}{n\left(1980+n\right)}+...+\frac{1}{25.2005}\)
B=\(\frac{1}{1.26}\)+\(\frac{1}{2.27}+...+\frac{1}{m\left(25+m\right)}+...+\frac{1}{1980+2005}\)
trong do Aco 25 so hang va B co 1980 so hang
tick jum mình sec cố gắng giải
chtt nghia la zj zax pan