Question

Horizontal tangent related problem. Actually need help understanding what it's asking xD

Answer 1

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Answer 2

The tangent is horizontal, that means the slope is 0 and also the derivative at that point must also be zero.

Answer 3

My long way is find the derivative of that function, then evaluate the derivative at the x co ordinates of those points given in the choices. The ones the give you zero is where the tangent is horizontal