Question

A graph is said to be _ if the tangent line lies _ the curve?

Answer 1

Without possible substitute words there are many possibilities, but I would guess:

A graph is said to be `\ bb ul("stationary") \` if the tangent line lies `\ bb ul("horizontal to") \` the curve?

Answer 2

Please see below.

Explanation:

As Steve has said, without any suggested words, there are many possible answers.

I would suggest:

A graph is said to be `bb ul("concave up") \` if the tangent line lies `bb ul("below")` the curve.

or

A graph is said to be `bb ul(concave" "down)` if the tangent line lies `bb ul(above)` the curve.

You may need to say "convex" rather than "concave up" and "concave" rather than "concave down"