平方差公式的内容（最后两题了,） 计算：（a+1)(a-1)(a²+1)(a四次方+1)(a八次方+1)

（a+1)(a-1)(a²+1)(a四次方+1)(a八次方+1)
=(a²-1)(a²+1)(a^4+1)(a^8+1)
=(a^4-1)(a^4+1)(a^8+1)
=(a^8-1)(a^8+1)
=a^16-1
(-2a+b)(3a-b)-(a+b)(a-b)
=（-6a²+5ab-b²）-（a²-b²）
=-7a²+5ab
a=1/2,b=-1
=-7*(1/4)+5*(1/2)*(-1)
=-7/4-10/4
=-17/4

(a+1)(a²+1)(a^4+1)(a^8+1)
=(a-1)(a+1)(a²+1)(a^4+1)(a^8+1)/(a-1)
=(a^2-1))(a²+1)(a^4+1)(a^8+1)/(a-1)
=(a^4-1))(a^4+1)(a^8+1)/(a-1)
=(a^8-1)(a^8+1)/(a-1)
=(a^16-1)/(a-1)
(-2a+b)(3a-b)-(a+b)(a-b)
=-6a^+2ab+3ab-a^2+b^2
=-7a^2+5ab
=-7*(1/2)^2+5*(1/2)*(-1)
=-7/4-5/2
=-17/4

a的十六次方-1
-17/4