已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值_数学解答

已知x=a+b,y=a-b,求(x²+y²)²-(x²-y²)²的值

人气：462 ℃　时间：2020-10-02 02:31:17

解答

原式=[(x²+y²)+(x²-y²)][(x²+y²)-(x²-y²)]=)2x1N)(2y²)=4(xy)²=4[(a+b)(a-b)]²=4(a²-b²)²=4a^4-8a²b²+4b^4