(2a^2-1)(4a^2+1)(16a^4+1)的值 2﹑9x+4)(x-4)-2x(1/2x+2)=0的值 3﹑(1-1/2^2)(1-1/3^2)…(1-1/9^2)
问题描述:
(2a^2-1)(4a^2+1)(16a^4+1)的值 2﹑9x+4)(x-4)-2x(1/2x+2)=0的值 3﹑(1-1/2^2)(1-1/3^2)…(1-1/9^2)
答
(4a^2-1)(4a^2+1)(16a^4+1)=(16a^4-1)(16a^4+1)=256a^8-1(x+4)(x-4)-2x(1/2x+2)=0x²-16-x²-4x=04x=-16x=-4(1-1/2^2)(1-1/3^2)…(1-1/9^2)=(1+1/2)(1-1/2)(1+1/3)(1-1/3)...(1+1/9)(1-1/9)=1/2x3/2x2...