Okay so I know for concavity we have to find the second derivative, but i'm not sure what to do after? Do I equal it to zero? or idk can someone help?
y=x^3-3x^2+4

Question

Okay so I know for concavity we have to find the second derivative, but i'm not sure what to do after? Do I equal it to zero? or idk can someone help?
 y=x^3-3x^2+4

phi · Answer

concavity is a property of the curve at every point on the curve
(similar idea as slope at every point on the curve)

once you have an expression for concavity, you can find where it changes concavity, 
to help in sketching the curve.  
Or you might want to know if a point is a local max or min. concavity tells you.

you will have to provide more info on your question to know exactly what you are trying to do.