Using differentiation rules, find a cubic function
y=ax^3+bx^2+cx+d
whose graph has horizontal tangents at (-2,6) and (2,0)

Do not graph on a calculator.

Question

Using differentiation rules, find a cubic function
y=ax^3+bx^2+cx+d
whose graph has horizontal tangents at (-2,6) and (2,0)

Do not graph on a calculator.

ash2326 · Answer

@Headdesk What's the slope of horizontal tangents or horizontal lines?

anonymous · Answer

Try differentiating your original function and setting that to 0 to start with.  Once you do that, then fill in the"x" and "y" and solve for a, b, and c.

anonymous · Answer

y' = 3ax^2 + 2bx + c   Now substitute the x and y for each point.  Solve for a, b, and c

anonymous · Answer

Okay, that makes more sense then how I was attempting to do it before. Thanks!

anonymous · Answer

Good luck in all of your studies and thx for the recognition!  And you're welcome! @Headdesk