( x - 1 ) x = 1
( x - 1 ) x = 11
=> x - 1 = 1
x = 1 + 1
x = 2
( x - 1 ) x = 1
( x - 1 ) x = 11
=> x - 1 = 1
x = 1 + 1
x = 2
tim x : 1/x(x+1)+1/(x+1)(x+2)+1/(x+2)(x+3)-1/1/2010
{1-1/2}x{1-1/3}x{1-1/4}x{1-1/5}x......x{1-1/2017}x{1-1/2018}
A = 1 + 1 x 2 + 1 x 2 x 3 + 1 x 2 x 3 x 4 + 1 x 2 x 3 x 4 x 5 + ........... + 1 x 2 x 3 x ....... x 100 .
ai giúp zới
b,(1-1/49)x(1-1/64)x(1-1/81)x(1-1/100)x(1-1/121)x(1-1/144)
tim tich: A= (1+1/1 x 3)x(1+1/2x4)x(1+1/3x5)x............x(1+1/2011x2013)
tim tich: A= (1+1/1 x 3)x(1+1/2x4)x(1+1/3x5)x............x(1+1/2011x2013)
(1-1/2)x(1-1/3)x(1-1/4)x...x(1-1/2004)
( 1 - 1/4 ) x ( 1 - 1/9 ) x ( 1 - 1/16 ) x ( 1 - 1/25 ) x ( 1 - 1/36 )
tính nhanh
b,(1-1/49)x(1-1/64)x(1-1/81)x(1-1/100)x(1-1/121)x(1-1/144)
\(\dfrac{x-1}{12}+\dfrac{x-1}{20}+\dfrac{x-1}{30}+\dfrac{x-1}{42}+\dfrac{x-1}{56}+\dfrac{x-1}{72}=\dfrac{16}{9}\)