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

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SUMMARY

The discussion focuses on finding the equations of tangent lines to the function f(x) = 4x - x² at the point P(2, 7), which is not on the graph of f(x). The user attempts to derive the slope using the derivative f'(x) = 4 - 2x and applies it to the line equation y = mx + b. The solution requires substituting the coordinates of point P into the tangent line equation to solve for b, ensuring the tangent lines intersect the graph of f(x) at the correct slope.

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  • Learn how to compute derivatives of polynomial functions using rules of differentiation.
  • Study the concept of tangents and normals in calculus.
  • Explore the application of the quadratic formula to find intersection points between curves.
  • Practice solving similar problems involving tangent lines to various functions.
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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.
 
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