\(y=\frac{1\times100+2\times99+3\times98...+99\times2+100\times1}{1\times2+2\times3+3\times4+...+99\times100+100\times101}=?\)
Tính :
A = \(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}+...+\frac{1}{2^{99}}+\frac{1}{2^{100}}\)
B = \(\frac{1}{1\times2}+\frac{1}{2\times3}+\frac{1}{3\times4}+...+\frac{1}{98\times99}+\frac{1}{99\times100}\)
\(\frac{1\times2}{2\times3}+\frac{2\times3}{3\times4}+\frac{3\times4}{4\times5}+...+\frac{98\times99}{99\times100}\)
\(\frac{7}{1\times3}+\frac{7}{3\times5}+\frac{7}{5\times7}+......+\frac{7}{99\times101}\)
Tính biểu thức A
\(A=\frac{5}{1\times2}+\frac{5}{2\times3}+\frac{5}{3\times4}+...+\frac{5}{98\times99}+\frac{5}{99\times100}\)
tính
\(P=\frac{\frac{1}{1}+\frac{1}{3}+\frac{1}{5}+...+\frac{1}{97}+\frac{1}{99}}{\frac{1}{1}.99+\frac{1}{3}.97+\frac{1}{5}.95+...+\frac{1}{97}.3+\frac{1}{99}.1}\)
Các bạn giúp mk, mk cần gấp!
\(\frac{4}{1\times3}+\frac{4}{3\times5}+\frac{4}{5\times7}+......+\frac{4}{99\times101}\)
\(H=\frac{\left(1+97\right)\left(1+\frac{97}{2}\right)\left(1+\frac{97}{3}\right)\left(1+\frac{97}{4}\right)+...+\left(1+\frac{97}{99}\right)}{\left(1+99\right)\left(1+\frac{99}{2}\right)\left(1+\frac{99}{3}\right)\left(1+\frac{99}{4}\right)+...+\left(1+\frac{99}{97}\right)}\)
CHỨNG TỎ:
\(\frac{2}{1\times3}\)+\(\frac{2}{3\times5}\)+\(\frac{2}{5\times7}\)+...+\(\frac{2}{99\times101}\)<1