求值(3+1/3)(3^2+1/3^2)(3^4+1/3^4)(3^8+1/3^8)(3^16+1/3^16),
问题描述:
求值(3+1/3)(3^2+1/3^2)(3^4+1/3^4)(3^8+1/3^8)(3^16+1/3^16),
我记得好像是6。
答
原式=(3-1/3)(3+1/3)……(3^16+1/3^16)/(3-1/3)
=(3^2-1/3^2)(3^2+1/3^2)(3^4+1/3^4)(3^8+1/3^8)(3^16+1/3^16)/(3-1/3)
=……
=(3^32+1/3^32)
=3(3^32+1/3^32)/8