问题标题:
【已知|a-1/2|+(b+2)^2=0求a^3-3a^2b+4ab^2-2b^2】
问题描述:
已知|a-1/2|+(b+2)^2=0求a^3-3a^2b+4ab^2-2b^2
罗宏保回答:
|a-1/2|+(b+2)^2=0
|a-1/2|>=0
(b+2)^2>=0
所以
|a-1/2|=0
(b+2)^2=0
a=1/2
b=-2
a^3-3a^2b+4ab^2-2b^2
=(a-b)^3+ab^2-b^2
=125/8-2+4
=141/8
罗宏保回答:
|a-1/2|+(b+2)^2=0|a-1/2|>=0(b+2)^2>=0所以|a-1/2|=0(b+2)^2=0a=1/2b=-2a^3-3a^2b+4ab^2-2b^2=(a-b)^3+ab^2-b^2=125/8-2+4=141/8
罗宏保回答:
|a-1/2|+(b+2)^2=0|a-1/2|>=0(b+2)^2>=0所以|a-1/2|=0(b+2)^2=0a=1/2b=-2a^3-3a^2b+4ab^2-2b^2=(a-b)^3+ab^2+b^3-2b^2=125/8-2+4-8=61/8
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