Expert: Ahmed Salami - 8/16/2004

Question
if I have a parabolic curve and I mark a dot or a point at the highest  part of the curve where it starts descending. and furthermore I draw  a tangent at this point. what is the formula of this tangent? Thank you very much.  Salvador.

Answer
Hi Salvador,
At the highest point, the tangent would just be horizontal. So it's equation is of the form y = k where k is a constant that happens to be the value of y at this highest point.
To add a few points,for a quadratic equation of the form
y = ax^2 + bx + c
The highest value of y occurs when x = -b/2a

I hope that helps you.
Regards.