Tangent line through arbitrary point?

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SUMMARY

The discussion centers on finding the slope of a line passing through the point A(4, 5) and an arbitrary point on the function f(x) = x² + 5x + 5. The derivative f′(x) = 2x + 5 is provided to assist in determining the slopes of tangent lines, which are identified as 1 and 25. However, the main task is to derive a formula for the slope between point A and any point on the parabola, clarifying that point A is not located on the graph of the function.

PREREQUISITES
  • Understanding of derivatives, specifically f′(x) = 2x + 5
  • Knowledge of the slope formula between two points
  • Familiarity with quadratic functions, particularly f(x) = x² + 5x + 5
  • Ability to identify points on a parabola
NEXT STEPS
  • Learn how to derive the slope formula between two points on a graph
  • Study the concept of tangent lines in calculus
  • Explore the properties of quadratic functions and their graphs
  • Investigate the implications of points not lying on a given curve
USEFUL FOR

Students studying calculus, particularly those focusing on derivatives and slopes of lines, as well as educators seeking to clarify concepts related to quadratic functions and tangent lines.

PandaherO
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Homework Statement



Consider the function f(x)=x2+5x+5 and the point A(4,5).

Find a formula for the slope of a line passing through point A, and an arbitrary point on the function. Your answer should be a formula in terms of x.
slope=?

Homework Equations



f′(x)=2x+5

The Attempt at a Solution



Using your answers from the two previous questions, find the slope(s) of the line(s) through point A that is (are) tangent to f(x)

the slopes are 1, and 25 however I don't understand what part two of the question is asking for...
(formula for slope passing through point A, and arbitrary point on the function)
 
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PandaherO said:

Homework Statement



Consider the function f(x)=x2+5x+5 and the point A(4,5).

Find a formula for the slope of a line passing through point A, and an arbitrary point on the function. Your answer should be a formula in terms of x.
slope=?

Homework Equations



f′(x)=2x+5

The Attempt at a Solution



Using your answers from the two previous questions, find the slope(s) of the line(s) through point A that is (are) tangent to f(x)

the slopes are 1, and 25 however I don't understand what part two of the question is asking for...
(formula for slope passing through point A, and arbitrary point on the function)

First off, your thread title seems misleading to me, as this problem has nothing to do with tangent lines. All they are asking for is the slope of a line that goes through A(4, 5) and an arbitrary point on the graph of y = x2 + 4x + 5. Note that A is not on the graph of this parabola.

The question boils down to finding the slope of the line through two points: A(4, 5) and some point on the graph of the parabola. What are the coordinates of each point on the parabola?
 

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