Answer:
The tangent line to the given curve at the given point is  .
.
Step-by-step explanation:
To find the slope of the tangent line we to compute the derivative of  and then evaluate it for
 and then evaluate it for  .
.
 Differentiate the equation.
          Differentiate the equation.
 Differentiate both sides.
       Differentiate both sides.
 Sum/Difference rule applied:
    Sum/Difference rule applied: 
 Constant multiple rule applied:
  Constant multiple rule applied: 
 Applied power rule:
        Applied power rule: 
 Simplifying and apply constant rule:
               Simplifying and apply constant rule: 
 Simplify.
                    Simplify.
Evaluate y' for x=4:


 is the slope of the tangent line.
 is the slope of the tangent line.
Point slope form of a line is:

where  is the slope and
 is the slope and  is a point on the line.
 is a point on the line.
Insert 9 for  and (4,10) for
 and (4,10) for  :
:

The intended form is  which means we are going need to distribute and solve for
 which means we are going need to distribute and solve for  .
.
Distribute:

Add 10 on both sides:

The tangent line to the given curve at the given point is  .
.
------------Formal Definition of Derivative----------------
The following limit will give us the derivative of the function  at
 at  (the slope of the tangent line at
 (the slope of the tangent line at  ):
):

 We are given f(4)=10.
  We are given f(4)=10.

Let's see if we can factor the top so we can cancel a pair of common factors from top and bottom to get rid of the x-4 on bottom:

Let's check this with FOIL:
First: 
Outer: 
Inner: 
Last: 
---------------------------------Add!

So the numerator and the denominator do contain a common factor.
This means we have this so far in the simplifying of the above limit:



Now we get to replace x with 4 since we have no division by 0 to worry about:
2(4)+1=8+1=9.