Question

D= 3/1.3+3/3.5+....................................+3/49.51

Answer 1

D = \(\frac{3}{1.3}\) + \(\frac{3}{3.5}\)+.......+ \(\frac{3}{49.51}\)

D = \(\frac{3.2}{1.3.2}\)+ \(\frac{3.2}{3.5.2}\)+ .....+ \(\frac{3.2}{49.51.2}\)

D = \(\frac{3}{2}\)( \(\frac{2}{1.3}\)+ \(\frac{2}{3.5}\)+...+ \(\frac{2}{49.51}\))

D = \(\frac{3}{2}\)( \(\frac{1}{1}\)- \(\frac{1}{3}\)+ \(\frac{1}{3}\)-\(\frac{1}{5}\)+ .....+ \(\frac{1}{49}\)- \(\frac{1}{51}\))

D = \(\frac{3}{2}\)( 1 - \(\frac{1}{51}\))

D = \(\frac{3}{2}\) x  \(\frac{50}{51}\)

D = \(\frac{25}{17}\)

Vậy D = \(\frac{25}{17}\)

**** xcho mình nha bn !!!! 

Answer 2

tại sao lạ là 3/2 hả bạn