问一道数学题..化简求值
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问一道数学题..化简求值
化简求值...其中x=9分之1 y=-3
![](http://img.wesiedu.com/upload/d/0f/d0f2bee8f4a7df8749959975aaf3c65f.jpg)
化简求值...其中x=9分之1 y=-3
![](http://img.wesiedu.com/upload/d/0f/d0f2bee8f4a7df8749959975aaf3c65f.jpg)
![问一道数学题..化简求值](/uploads/image/z/6985229-5-9.jpg?t=%E9%97%AE%E4%B8%80%E9%81%93%E6%95%B0%E5%AD%A6%E9%A2%98..%E5%8C%96%E7%AE%80%E6%B1%82%E5%80%BC)
(x+y^2)+[2x+y^2/(1*2)]+[3x+y^2/(2*3)]+
+[3x+y^2/(3*4)]+...+[9x+y^2/(8*9)]
=x+2x+3x+...+9x+y^2[1+1/(1*2)+1/(2*3)+...+1/(8*9)]
=(1+9)*9x/2+y^2(1+1-1/2+1/2-1/3+.+1/8-1/9)
=45x+(1+1-1/9)y^2
=45x+17y^2/9
=45*1/9+17/9*(-3)^2
=5+17/9*9
=5+17
=22
+[3x+y^2/(3*4)]+...+[9x+y^2/(8*9)]
=x+2x+3x+...+9x+y^2[1+1/(1*2)+1/(2*3)+...+1/(8*9)]
=(1+9)*9x/2+y^2(1+1-1/2+1/2-1/3+.+1/8-1/9)
=45x+(1+1-1/9)y^2
=45x+17y^2/9
=45*1/9+17/9*(-3)^2
=5+17/9*9
=5+17
=22