omg: determine the point on the curve where the tangent line to the curve is horizontal. (The answer must be a POINT on the curve.)

Question

anonymous · Answer

attachment

anonymous · Answer

tangent line horizontal at the vertex, so you are really being asked to find the vertex is 
$$y=-x^2-6x+2$$

anonymous · Answer

oh i know find derivative! right?

anonymous · Answer

first coordinate of the vertex is always $-\frac{b}{2a}$ which in your case is $-\frac{-6}{2\times -1}=-3$

anonymous · Answer

and then plug in what x is to the normal function.

anonymous · Answer

yes i got that :)

anonymous · Answer

thank you @satellite73 you refreshed my memory =]

anonymous · Answer

or you can take the derivative, set it equal to zero and solve, which is rather silly because you will still get $-\frac{b}{2a}$ no need for calculus when you have a quadratic

anonymous · Answer

yw