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已知数列an中,a1=1,an+1=an/1+2an,则a6=

题目详情
已知数列an中,a1=1,an+1=an/1+2an,则a6=
▼优质解答
答案和解析
=-4,b=27,c=16
所以原式=-a+b-c=4+27-16=15
xy-2{xy-[3x2y-(xy2+0.5xy)]+4x2y}
=xy-2xy+2[3x2y-(xy2+0.5xy)]-8x2y
=-xy+6x2y-2(xy2+0.5xy)-8x2y
=-xy-2x2y-2xy2-xy
=-2xy-2x2y-2xy2
=-4-4-8
=-16