### Home > CALC > Chapter 12 > Lesson 12.2.3 > Problem 12-97

12-97.

If the tangent line is horizontal, the *dy* = 0.

If the tangent line is vertical, then *dx* = 0.

12-97.

If the tangent line is horizontal, the *dy* = 0.

If the tangent line is vertical, then *dx* = 0.