# Question #c4080

##### 1 Answer

#### Explanation:

Firstly we note that at a vertex (max/min) the tangent will be horizontal (

**Method 1 (pre-calculus):**

Complete the square:

So a minimum occurs when

**Method 2 (Calculus):**

differentiating wrt

At a max/min

We observe that as the function is a positive quadratic it will have a U shared curve, so this corresponds to a minimum

**Finding the tangent:**

So back to business, we now know that the min occurs when

So the equation of the tangent at the vertex (corresponding to