I'm trying to understand something. Derrivatives are basically the same as differentials. The both apply to the chnange in XY values. Now I have an eqaition y=x*x x*x=x sqaured. So that being here are my XY values X y _______ 1 1 2 4 3 9 4 16 5 25 So that being dv=2x . But if you plug that in x the change is different. WIth that eqauition if x=1 the change in y should be 2. So if x changes by 1. But is chnage x by 1 y becomes 4. If x=2 the change in y should be 4. But if we change x by 1 y=9 not 8. What's going on?