Tangent Lines to f(x) at Point (2,7)

In summary, the problem is to find the equations of lines passing through a point (2,7) that are tangent to the graph of f(x) = 4x-x^2, where the point is not on the graph. The attempt at a solution involved finding the derivative of f(x) and using it in the equation for a line, but it is unclear if this approach is correct. A similar problem can be found on a physics forum.
  • #1
Squiller
6
0

Homework Statement



f(x) = 4x-x2

Question: Find the equations of the lines that pass through P(2,7) and are tangent to the graph of f(x).

(P is not on f(x).)
Thats all the problem states.

Homework Equations



f(x) = 4x-x2
Point (2,7)

The Attempt at a Solution



Ive tried finding f'(x) and plugging f' into the Line equation y=mx+b.

y=(4-2x)x+b.

Then plugging in Point P.

7=(4-2x)2+b - I am not really sure if this is heading in the right direction.
 
Physics news on Phys.org

1. What is a tangent line to a function?

A tangent line to a function is a line that touches the function at exactly one point. This point of tangency has the same slope as the function at that point.

2. How do you find the equation of a tangent line to a function?

To find the equation of a tangent line to a function, you need to first find the derivative of the function. Then, you can use the point-slope form of a line to plug in the coordinates of the point of tangency and the slope of the function at that point.

3. What is the significance of a tangent line in calculus?

In calculus, the tangent line is used to approximate the behavior of a function at a specific point. It can also help us find the instantaneous rate of change, or the derivative, of a function.

4. Can a function have more than one tangent line at a point?

No, a function can only have one tangent line at a point. This is because a tangent line must touch the function at exactly one point and have the same slope as the function at that point.

5. What is the relationship between the slope of a tangent line and the derivative of a function?

The slope of a tangent line is equal to the derivative of the function at the point of tangency. This means that the derivative gives us the slope of the tangent line, and vice versa.

Similar threads

  • Calculus and Beyond Homework Help
Replies
1
Views
128
  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
2
Views
599
  • Calculus and Beyond Homework Help
Replies
8
Views
468
  • Calculus and Beyond Homework Help
Replies
11
Views
1K
  • Calculus and Beyond Homework Help
Replies
9
Views
1K
  • Calculus and Beyond Homework Help
Replies
13
Views
3K
  • Calculus and Beyond Homework Help
Replies
2
Views
511
  • Calculus and Beyond Homework Help
Replies
6
Views
983
  • Calculus and Beyond Homework Help
Replies
15
Views
1K
Back
Top