設f(x)是一個三次多項式,若f(1)=1,f(2)=2,f(4)=-2 且(5)=5,则f(x) =
2-x^t I X ID__。(答案請依降冪排列寫出)
**3> fx = x = f(x+ x = 0
(1> f(x) = ax² + b + cxtd
f(x)-X = (X-U (x-2)(X-5)2(x)
</27 f(x) = a(x-7)(x-2)(x-4)
+b(x-1) (X -27
- f(x) = (x-7)(x-2)(x-5) a+x
tc (x-1)
It f(4) a=1
td (x-1)