[1-1/2²)][1-1/3²)][1-1/4²)][1-1/5²)][1-1/6²)][1-1/7²)][1-1/8²)][1-1/9²)][1-1/10²)]=(1-1/2)(1+1/2)(1-1/3)(1+1/3)(1-1/4)(1+1/4).(1-1/10)(1+1/10)=(1/2)(3/2)(2...