giup minh 4/1x3+4/3x5+4/5x7+4/7x9+....+4/17x19+4/19x21
K=\(\dfrac{4}{1x3}\)+\(\dfrac{4}{3x5}\)+\(\dfrac{4}{5x7}\)+...+\(\dfrac{4}{297x299}\)+\(\dfrac{4}{299x301}\)
a=1/1x2 + 1/2x3+ 1/3x4 +...1/99x100
b=4/1x3+4/3x5+4/5x7 +...+4/51x53
\(\frac{4}{1X3}+\frac{4}{3X5}+\frac{4}{5X7}+.......+\frac{4}{11X13}\)= ?
Tính:
1, A = 1/1x3 + 1/3x5 + 1/5x7 + ... + 1/2019 x 2021
2, B= 4/11x16 + 4/16x21 + 4/21x26 + ... + 4/61x66
Tính :
A = 2/1x3 - 4/3x5 + 6/5x7
A = 4/1x3+16/3x5+36/5x7+...+2500/49x51
tính tổng của A
4/1x3 - 8/3x5 + 12/5x7 -16/7x9 + 20/9x11 - 24/11x13
giúp mình giải bài nay với ạ
a,1/1x3+1/3x5+1/5x7+1/7x9+1/X=1;b,2/3-1/3x(X-2)=1/4