(1 - 1/2)(1 - 1/3)(1 - 1/4)*...*(1 - 1/2006)
= [(2² - 1)/2²]*[(3² - 1)/3²)*[(4² - 1)/4²)*...*[(2006² - 1)/2006²]
= [(2 - 1)(2 +1)/2²][(3 -1)(3 + 1)/3²]*[(4 - 1)(4 + 1)/4²]*...*[(2006 - 1)(2006 + 1)/2006²]
= 1*3*2*3*3*5*...*2004*2006/(2²*3²*4²*...*2006²)
= 1*2*3²*4²*...*2005²*2006*2007/(2²*3²*4²*...*2006²)
= 1*2*2006*2007/(2²*2006²)
= 2007/4012
(1-1/2*2)(1-/3*3)(1-/4*4).....(1-/2006*2006)
=2007/(2 *2006)
=2007/4012