what is "igamma" exactly

hello my friends I try to use the following integral:

q=int(exp(-0.0245*x)*x^-0.9755,0,99.2)

the answer is:

q=(7^(951/1000)*2000^(49/2000)*(gamma(49/2000) - igamma(49/2000, 1519/625)))/7

whats wrong with this solution. I have tried some numerical integration, but the answers are not my desired solution. could you please give me some appropriate ways to solve this kind of integration. Thank you

Answer 1

[John D'Errico]

igamma is the incomplete gamma function. It is also available in MATLAB proper as gammainc. As far as I can see, that solution seems at least reasonable.

What is not to your liking about the result? Don't just say that you don't like a result. WHAT don't you like? All that we can do is guess. Here is my guess.

vpa(q)
ans =
44.062223875034479994516141234239