Question

So sánh A và B : 

A = 1/31 + 1/32 + 1/33 + ....+ 1/60

B = 1/1.2 + 1/3.4 + ....+ 1/59.60

Giúp tớ với tớ đang vội

Answer 1

\(B=\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{59.60}\)

\(B=1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{59}-\frac{1}{60}\)

\(B=\left(1+\frac{1}{3}+...+\frac{1}{59}\right)-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{60}\right)\)

\(B=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+..+\frac{1}{59}+\frac{1}{60}\right)-2.\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{50}\right)\)

\(B=\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{49}+\frac{1}{50}\right)-\left(1+\frac{1}{2}+...+\frac{1}{30}\right)\)

\(B=\frac{1}{31}+\frac{1}{32}+\frac{1}{33}+...+\frac{1}{60}=A\)

Answer 2

A > B nhé tích mk vs

Answer 3

cậu giải giúp tớ cái