原式=a^8+a^4b^4+1/4b^8-a^4b^4
=(a^4+1/2b^4)²-a^4b^4
=(a^4+a²b²+1/2b^4)(a^4-a²b²+1/2b^4)a^4b^4=(a^2 2b^2)^2吧嗯