(1+五分之二)*(1-五分之二)*(1-七分之二)*(1-七分之二)*···*(1+两千零五分之二)*(1-两千零五分之二)要完整的算式,

问题描述:

(1+五分之二)*(1-五分之二)*(1-七分之二)*(1-七分之二)*···*(1+两千零五分之二)*(1-两千零五分之二)
要完整的算式,

=(1-(2/5)²)*(1-(2/7)²)......(1-(2/2005)²)=((5²-2²)/5²)*((7²-2²)/7²)*........*((2005²-2²)/2005²)=(3*7*5*9*7*11.......2003*2007)/(5²*7²*9²....2005²)=(3*5*2005*2007)(5²*2005²)=(3*2007)/(5*2005)剩下的自己去算吧....

= 7/5 * 3/5 * 9/7 * 5/7 * 11/9 * 7/9 *……*2007/2005 * 2003/2005
=3/5 * 2007/2005
=6021/ 10025