(1)(1+1/2)(1+1/2的二次方)(1+1/2的四次方)(1+1/2的八次方)(1+1/2的十六次方)
＝2*(1-1/2)*)(1+1/2)(1+1/2的二次方)(1+1/2的四次方)(1+1/2的八次方)(1+1/2的十六次方)
=2(1-1/2^2)(1+1/2的二次方)(1+1/2的四次方)(1+1/2的八次方)(1+1/2的十六次方)
=2*(1-1/2^4)(1+1/2的八次方)(1+1/2的十六次方)
.
=2*(1-1/2^32)
=2-1/2^31
(2)(3+1)(3的二次方+1)(3的四次方+1).(3的2次方的n次方+1)
=1/2*(3-1)(3+1)(3的二次方+1)(3的四次方+1).(3的2次方的n次方+1)
=1/2*(3^2-1)(3的四次方+1).(3的2次方的n次方+1)
...
=1/2*(3^(4n)-1)
=[3^(4n)-1]/2