maple

Differentiating a piecewise function

I am trying to differentiate the piecewise function shown in the picture below using Maple
enter image description here

However when I assign the piecewise function to H using the following code

H := piecewise(gamma <> 0, exp(-(1 + gamma*(x - alpha)/beta)^(-1/gamma)), gamma = 0, exp(-exp(-(x - alpha)/beta)))

the function when γ=0 is being ignored and I am not sure why. I am getting the following output
enter image description here
As a result, when I try to find the derivative with respect to x, the derivative when γ=0 is omitted. I am kindly seeking assistance on how to resolve this problem.

Solution

  • The name gamma is a predefined constant in Maple.

    evalf(gamma);

        0.5772156649

    You could first declare is local at the top-level, or you could use another name.

    For example,

    restart;
local gamma;

H := piecewise(gamma <> 0,
               exp(-(1 + gamma*(x - alpha)/beta)^(-1/gamma)),
               gamma = 0,
               exp(-exp(-(x - alpha)/beta)));