Sorry for the bump, but I really need help.
Let for and is greater than or equal to 0. The line tangent to the graph of at the point intercepts the x-axis at . What is the value of k?
--> tangent line
I know it's wrong because the tangent line is and is tangent at .
How would one go about doing it correctly?
Consider what you know about the derivative.
You know that you are looking for a tangent line at the point . You also know that the derivative of your function is linear so it will have a constant slope. Consider what is happening between the points and where it intersects the x-axis.
Use what you know about the slope between and and the fact that the derivative represents a slope to help you solve for k.
Hope these hints help.