If what is/are the local maximum value/values of  f. Only write the number/numbers separating by "," . If there is no maximum value answer "no"

Consider the function .  What is the directional derivative at the point in the direction ?

Let . Then at the point , compute  

Let . Compute .

grad (f) is a vector.

 Directional derivative is a vector.

The angle between the planes and is where is equal to  

Let

be the plane passing through the points

Where does the line

Write down a normal vector to the plane .

Write the answer in < > form

Write down an equation for the plane passing through the points

Express your answer in the form