待定系数法应用已知:x^3-9x^2+25x+13=a(x+1)(x-2)(x-3)=b(x-1)(x-2)(x-3)=c(x-1)(x+1)(x-3)=d(x-1)(x+1)(x-2).求:a+b+c+d的值.
问题描述:
待定系数法应用
已知:x^3-9x^2+25x+13=a(x+1)(x-2)(x-3)=b(x-1)(x-2)(x-3)=c(x-1)(x+1)(x-3)=d(x-1)(x+1)(x-2).求:a+b+c+d的值.
答
题出错了
答
题错.令x=1,→a=0. x=-1→b=0, x=2→c=0. x=3→d=0.a+b+c+d=0
x^3-9x^2+25x+13≡0.不可.