How to calculate the integral of function y=((-1100.​/9.4182)*e​xp((1.17*1​40.^(1/3)-​x)./0.574)​+(1.774*10​.^(-14))./​x-1).^0.5 ?

I did it myself, but there's something wrong with the answer. Here is what I did. First, In M-File I wrote function y=myfun(x) y=((-1100./9.4182)*exp((1.17*140.^(1/3)-x)./0.574)+(1.774*10.^(-14))./x-1).^0.5; then in command window I wrote Q=quadl(@myfun,7.2696*10.^(-15),1.774*10.^(-14)) and the answer is Q =

     1.377030900487298e-027 +2.248862123260422e-011i
I don't understand the answer. Help me

Answer 1

[Georgios]

The answer is correct, from a Matlab perspective. As used, the quadl function returns and answer to within an error of 10e-6, according to the help page. You can change this by giving it a third argument, which is smaller than the default 10e-6, but the answer you get will not change much.

The first part of the answer (1.377030900487298e-027)tells me that there is no real part to it, and the second part(2.248862123260422e-011i)tells me that the imaginary value is very small, but correct. I tried your integral using another software package and the answer returned was 2.248862122*10^(-11)*I, which is equivalent to your answer.

Hope this helps.

Regards, Georgios

[Walter Roberson]

Georgios' result is the same as what I get.