Hey, could someone please help me with the second part of this question. Thanks!

g(x) = ln x ; x > 1

1.7^{x}- C ; x != 1

(a) Determine the value(s) of C for which this function is continuous at x = 1.

(b) With each value of C found in (a), determine from first principles if g is differentiable at x = 1.

For the first part I got C = 1.7, I'm unsure how to do part b.