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: The derivative of a constant is 0. The derivative of a power function is n * x^(n-1). 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)