The figure below shows the graph of and the graph of its local linearization at . (The local linearization is shown in blue.)

a graph of a concave up function, in black, with a line, in blue, tangent to the curve when x=2

What is the value of ?

What is the value of ?

Use the linearization to approximate the value of .

Is the approximation an under- or overestimate?
(Enter under or over.)

You can earn partial credit on this problem.