I've just given you good arguments for when you're not continuous, you're not going to be differentiable. But can we make another claim that if you are continuous, then you definitely will be differentiable? Well it turns out that there are for sure many functions, an infinite number of functions, that can be continuous at C but not differentiable. So for example, this could be an absolute value function. It doesn't have to be an absolute value function, but this could be Y is equal to the absolute value of X minus C. And why is this one not differentiable at C? Well think about what's happening. Think about this expression.