\(-2\left(\dfrac{1}{30\cdot32}+\dfrac{1}{32\cdot34}+\dfrac{1}{34\cdot36}\right)\)
\(=-2\cdot\dfrac{1}{2}\cdot\left(\dfrac{2}{30\cdot32}+\dfrac{2}{32\cdot34}+\dfrac{2}{34\cdot36}\right)\)
\(=-1\left(\dfrac{1}{30}-\dfrac{1}{32}+\dfrac{1}{32}-\dfrac{1}{34}+\dfrac{1}{34}-\dfrac{1}{36}\right)\)
\(=\dfrac{1}{36}-\dfrac{1}{30}=-\dfrac{1}{180}\)
\(\left(-2\right).\left(\frac{1}{30.32}+\frac{1}{32.34}+\frac{1}{34.36}\right)\)
\(A=\frac{6}{2.4}+\frac{6}{4.6}+\frac{6}{6.8}+\frac{6}{8.10}+....+\frac{6}{30.32}+\frac{6}{32.34}\)
Tính A
tính: 1/2.4 + 1/4.6 + 1/6.8 +...+1/30.32 =?
a, 1/3.4+1/4.5+..........+1/20.21
b, 1/4.6 + 1/6.8 +.............+ 1/30.32
a, 1/3.4+1/4.5+..........+1/20.21
b, 1/4.6 + 1/6.8 +.............+ 1/30.32
S=2.4+4.6+6.8+...+32.34
Tính nhanh.
30.32+30.88+70.73+70.47(chấm là nhân )
viết tích 32.34 dưới dạng lũy thừa của một số là: A.3⁸ B.6⁶ C.6⁸ D3⁶
