初二数学题,学霸快来呀。
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1、原式=2011^2-2011*2010*2+2010^2=(2011-2010)^2=1^2=1
2、原式=3.14(5.5^2-4.5^2)=3.14[(5+0.5)^2-(5-0.5)^2]
=3.1 4(5^2+2*5*0.5+0.5^2-5^2+2*5*0.5-0.5^2)
=3.14*10
=31.4
3、原式=(2012+2011)(2012-2011)+(2010+2009)()2010-2009)+……+(2+1)(2-1)
=2012+2011+2010+2009+……+2+1
=(2012+1)+(2011+2)+(2010+3)+……+(1007+1006)
=2013*1006
=2025078
2、原式=3.14(5.5^2-4.5^2)=3.14[(5+0.5)^2-(5-0.5)^2]
=3.1 4(5^2+2*5*0.5+0.5^2-5^2+2*5*0.5-0.5^2)
=3.14*10
=31.4
3、原式=(2012+2011)(2012-2011)+(2010+2009)()2010-2009)+……+(2+1)(2-1)
=2012+2011+2010+2009+……+2+1
=(2012+1)+(2011+2)+(2010+3)+……+(1007+1006)
=2013*1006
=2025078
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