f(z) = -2.5^z ( find the derivative)

 The derivative of f(z) = -2.5^z is -2.5^z * ln(2.5).

To find the derivative, we can use the following steps:

1. The derivative of a constant is 0.
2. The derivative of a power function is n * x^(n-1).
3. The derivative of ln(x) is 1/x.

Therefore, the derivative of f(z) = -2.5^z is:

f'(z) = -2.5^z * ln(2.5)