basic definition of a limit
lim x --> c f(x) = Las x gets closer and closer to c, but not equal to c, the values of f(x) get closer and closer to the value L
continuity
a function f is continuous at a point x = c if lim x-->c f (x) = f (c)(it has no holes, jumps or gaps)
differentiability
a function f is said to be differentiable at x = c if the limitlim x-->c (f(x) - f(c)) / x - c exists(at any point there is a well defined tangent line, smooth, no sharp points)*if differential it must be continuous (but reverse isn't true)
Factor (A + B)3
A3 + 3A2B + 3AB2 + B3