[Toán 7]_Đại số

L

leemin_28

Ta có: S=151+152+...+1100S=\dfrac{1}{51}+\dfrac{1}{52}+...+\dfrac{1}{100}
S=151+152+...+1100>1100+1100+...+1100(100pha^nso^ˊ1100)S=\dfrac{1}{51}+\dfrac{1}{52}+...+\dfrac{1}{100} > \dfrac{1}{100}+\dfrac{1}{100}+...+\dfrac{1}{100} ( 100 phân số\dfrac{1}{100})

S=151+152+...+1100>50.1100S=\dfrac{1}{51}+\dfrac{1}{52}+...+\dfrac{1}{100}> 50. \dfrac{1}{100}
S=151+152+...+1100>50100=12S=\dfrac{1}{51}+\dfrac{1}{52}+...+\dfrac{1}{100}> \dfrac{50}{100}= \dfrac{1}{2}
( ĐPCM)
 
Top Bottom