1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
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![1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.](/uploads/image/z/1967269-13-9.jpg?t=1.%E5%B7%B2%E7%9F%A5A%3D%E4%B8%802xy%26%23178%3B%2CB%3D%E4%B8%801%2F4x%26%23179%3B%2Bx%26%23178%3By-3xy%26%23178%3B-1%2F6y%26%23179%3B%2C%E6%B1%82A%26%23179%3BB.2.%E8%AE%BEm%26%23178%3B%2B2m%2B1%3D0%2C%E6%B1%82m%26%23179%3B%2B2m%26%23178%3B%2B2008%E7%9A%84%E5%80%BC.3.%E6%A2%AF%E5%BD%A2%E7%9A%84%E4%B8%8A%E5%BA%95%E9%95%BF%E4%B8%BA%284n%2Bm%29%E5%8E%98%E7%B1%B3%2C%E4%B8%8B%E5%BA%95%E9%95%BF%E4%B8%BA%282m%2B5n%29%E5%8E%98%E7%B1%B3%2C%E9%AB%98%E4%B8%BA%289n%2B3m%29%E5%8E%98%E7%B1%B3%2C%E6%B1%82%E6%AD%A4%E6%A2%AF%E5%BD%A2%E7%9A%84%E9%9D%A2%E7%A7%AF.)
1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.
2.设m²+2m+1=0,求m³+2m²+2008的值.
3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
1.已知A=一2xy²,B=一1/4x³+x²y-3xy²-1/6y³,求A³B.2.设m²+2m+1=0,求m³+2m²+2008的值.3.梯形的上底长为(4n+m)厘米,下底长为(2m+5n)厘米,高为(9n+3m)厘米,求此梯形的面积.
A^3B=(-2xy^2)^3(-1/4x^3+x^2y-3xy^2-1/6y^3)
=(-8x^3y^6)(-1/4x^3+x^2y-3xy^2-1/6y^3)
=2x^6y^6-8x^5y^7+24x^4y^8+4/3x^3y^9
m^3+2m^2+2008=m^3+2m^2+m-m+2008=m(m^2+2m+1)-m+2008=2008-m
从已知条件,可以求得:m=-1
所以,所求式子的值为:2008-m=2008-(-1)=2009
根据梯形面积公式得:梯形的面积为:
1/2[(4n+m)+(2m+5n)](9n+3m)=1/2(9n+3m)^2=81/2*n^2+9/2*m^2+27nm
2、(m+1)^2=1 m=-1 m^3+2m^2+2008=2009
3、S=0.5((4n+m)*(2m+5n)*(9n+3m))