在(1+x+px^2)^10的展开式中,试求使的x^4系数为最小值时p的值

(1+(x+px^2))^10
先这么展开
然后存在x^4的是第3,4和第5项
再展开这3项
C10,2p^2+C10,3*C3,1p+C10,4

呀 不对啊 我算的怎么也是360呢？？？？？？？？？？？？？

不是答案错了吧？？？？？？？？？？？。。。。。。。。

貌似p=-4啊。。。。。。

你等我用matlab展开一下试试

ans =

1+10*x+10*p*x^2+90*p*x^3+45*p^2*x^4+360*p*x^4+360*p^2*x^5+120*p^3*x^6+840*x^5*p+1260*x^6*p^2+840*p^3*x^7+210*p^4*x^8+45*x^2+120*x^3+210*x^4+252*x^5+1260*x^6*p+2520*x^7*p^2+2520*p^3*x^8+1260*p^4*x^9+252*p^5*x^10+3150*p^2*x^8+4200*p^3*x^9+3150*p^4*x^10+1260*p^5*x^11+1260*p*x^7+210*p^6*x^12+2520*p^2*x^9+4200*p^3*x^10+4200*p^4*x^11+2520*p^5*x^12+840*p*x^8+840*p^6*x^13+120*p^7*x^14+1260*x^10*p^2+2520*x^11*p^3+3150*x^12*p^4+2520*x^13*p^5+360*x^9*p+1260*x^14*p^6+360*p^7*x^15+45*p^8*x^16+210*x^6+120*x^7+45*x^8+10*x^9+x^10+90*x^10*p+360*x^11*p^2+840*x^12*p^3+1260*x^13*p^4+1260*x^14*p^5+840*x^15*p^6+360*x^16*p^7+90*p^8*x^17+10*p^9*x^18+10*x^11*p+45*x^12*p^2+120*x^13*p^3+210*x^14*p^4+252*x^15*p^5+210*x^16*p^6+120*x^17*p^7+45*x^18*p^8+10*p^9*x