Finding k Values for Tangency of y=kx-2 and f(x) = x^2

  • Thread starter Carl_M
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In summary, the process for finding k values for tangency involves setting two equations equal to each other, solving for x, and then substituting that value into either equation to solve for k. It is possible for more than one k value to result in tangency, as there can be multiple points of intersection with the same slope. The k value represents the slope of the tangent line at the point of intersection. There are restrictions on the k value, as it cannot be 0 or 1 in order for tangency to occur. A graphing calculator can be used to find k values, but it is important to also understand the mathematical process.
  • #1
Carl_M
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Homework Statement


For what values of k is the line y = kx - 2 tangent to the graph of f(x) = x^2?


Homework Equations





The Attempt at a Solution



Would I just find f'(x) = 2x?
 
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  • #2
Carl_M said:

The Attempt at a Solution



Would I just find f'(x) = 2x?

No but solving y=kx-2 and y=x2 would yield only one solution for x

Hint: recall the condition in the quadratic equation formula for equal roots.
 

FAQ: Finding k Values for Tangency of y=kx-2 and f(x) = x^2

What is the process for finding k values for tangency?

The process for finding k values for tangency involves setting the equations y=kx-2 and f(x) = x^2 equal to each other, solving for x, and then substituting that value of x into either equation to solve for the corresponding value of k.

Can more than one k value result in tangency?

Yes, it is possible for more than one k value to result in tangency between the two equations. This is because there can be multiple points where the two curves intersect and have the same slope.

What does the k value represent in this scenario?

The k value represents the slope of the tangent line where the two curves intersect. It is the rate of change of the line at that specific point.

Are there any restrictions on the k value?

Yes, there are restrictions on the k value in order for tangency to occur. The k value cannot be equal to zero, as that would result in a horizontal line which does not intersect with the parabola. Additionally, the k value cannot be equal to 1, as that would result in the two equations being identical and not intersecting at all.

Can I use a graphing calculator to find the k values?

Yes, a graphing calculator can be used to find the k values by graphing the two equations and finding the points of intersection. However, it is important to also understand the mathematical process for finding k values in case a calculator is not available.

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