# Question #3fc87

##### 2 Answers

#### Explanation:

Evaluated at

Let me try to explain more

#### Explanation:

Write F as (x-a) times G(x) where G is all the factors of F except the first one.

its derivative is (using the product rule)

F'(x) = (x-a) G'(x) + (x-a)'G(x)

so far so good.

Now for the value x = a, the first term vanishes, The derivative of

F(x) = (x-a)(x-b)(x-c)(x-d)(x-e)(x-f)

F'(a) = (a-b)(a-c)(a-d)(a-e)(a-f)

That is a very simple expression to remember, but not so easy to derive!