What do superscripted numbers inside parentheses on functions mean?

Question

I have a function $G(t) = (tx + (1 - x))^p = \sum\limits_{k=0}^pB_k^p(x)t^k$.

I must find two different expressions for $G^{(j)}(1)/j!$. What does the superscript $(j)$ mean in this case?

Answer 1

It means the $j$-th derivative of $G$.