Question

1.In a graph, the dependent quantity is shown on Y-axis and the independent quantity is shown on X-axis. 2.In a graph, the dependent quantity is shown on X-axis and the independent quantity is shown on Y-axis. 
A)Only sentence 1 is correct.
B)Only sentence 2 is correct.
C)Both can be correct according to the conditions.
D)Can not say​

Answer 1

Explanation:

X(z) is the z-transform of the signal x(n), then what is the z-transform of the signal nx(n)? Therefore, we get -z\frac{dX(z)}{dz} = Z{nx(n)}.