Rút gọn các biểu thức sau:
a) A = 1+1/3^2+1/3^3+...+1/3^n
b) B = 1/2-1/2^2+1/2^3-1/2^4+...+1/2^99-1/2^100
c) C = 3/2^2 x 8/3^2 x 15/4^2 ... 899/30^2
Rút gọn phân số
a,\(S=1+\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^n}.\)
b,\(C=\left(\frac{1}{2}+1\right)\left(\frac{1}{3}+1\right)\left(\frac{1}{4}+1\right).....\left(\frac{1}{99}+1\right)\)
c,\(D=\frac{3}{2^2}.\frac{8}{3^2}.\frac{15}{4^2}...\frac{899}{30^2}\)
3/2^2 * 8/3^2 * 15/4^2*......*899/30^2
Tính:
3/2^2 . 8/3^2 . 15/4^2 ..... 899/30^2
tính
3/2^2*8/3^2*15/4^2*...*899/30^2
Tính A= 3/22.8/32.15/42...899/302.
\(A=\frac{3}{2^2}.\frac{8}{3^2}\frac{15}{4^2}.....\frac{899}{30^2}\)
tính 3/22.8/32.15/42...899/302
3/22 . 8/32 . 15/42 ......899/302
