Question

ajutorrr urgentt e pentru mâine ​

Answer 1

Răspuns:

E(x) = (x+1)² - (x-1)²

E(x) = x²+2x+1 - ( x²-2x+1)

E(x) = 2x + 2x

E(x) = 4x

E(1) = 4

E(2) = 8

E(3) = 12

......

E(2009) = 8036

--------- +

4+8+12+.....+8036 = 4(1+2+......+2009)

= 4 * 2009 * 2010 / 2

= 2009 * 4020