[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)

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[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)

[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)
[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)

[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)
[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^2-1/2y^4)
用完全平方公式展开
=(18x^2+1/2y^4)(18x^2-1/2y^4)
用平方差公式
=18^2*x^4-1/4*y^8

题目中(18x^2-1/2y^4)应该是(18x^4-1/2y^4)吧?!如果是,解题如下:
[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^4-1/2y^4)
=[(9x^4 - 3x²y²+ 1/4 y^4)+(9x^4 + 3x²y²+ 1/4 y^4)](18x^4-1/2y^4)
=(18x^4 ...

全部展开

题目中(18x^2-1/2y^4)应该是(18x^4-1/2y^4)吧?!如果是,解题如下:
[(3x^2-1/2y^2)^2+(3x^2+1/2y^2)^2](18x^4-1/2y^4)
=[(9x^4 - 3x²y²+ 1/4 y^4)+(9x^4 + 3x²y²+ 1/4 y^4)](18x^4-1/2y^4)
=(18x^4 + 1/2 y^4)(18x^2-1/2y^4)
=324x^8 - (1/4)y^8

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