The limit as x approaches 0 of sine of x is 0, and the limit as x approaches 0 of x is also equal to 0. We get our indeterminate form. Let's see at least whether this limit even exists. If we take the derivative of f of x and we put that over the derivative of g of x and take that the limit as x approaches 0 in this case, that's our c. Let's see if this limit exists. I'll do that in the blue. Let me write the derivatives of the two functions. f prime of x, if f of x is sine of x, what's f prime of x?