MATLAB: Question about Symbolic math result

symbolic

I use symbolic math to calculate mean value of some RV(Random variable)
But when i typed "int(k*Pk,k,0,inf)" the result is just repeated one.
result:
ans =
int((55185267405035624650056728991236096*exp(-(25*log((1250*k)/87067)^2)/(8*log(10)^2)))/(1829132633092549724288256200758875*(k + (87067*z)/1250)^2), k, 0, Inf)
I like to know integer value of result.
How can i find it ?
Below code is what i used.
—————————————————————————————
syms k z
th=100;
sigma=sqrt(16);
alpha=69.6536;
Pk=10/(sigma*log(10)*k*sqrt(2*pi))*exp(-(10*log10(k/alpha))^2/(2*sigma^2));
int(k*Pk,k,0,inf);
—————————————————————————————

Best Answer

Using a different symbolic package, I found that the package was not able to do the integral directly, but that when I asked to convert to elliptic it did the integral without difficulty. The effect of the conversion appears to have been to rewrite a ln((1250/87067)*k)^2 term into a sum and difference of ln() obtained by factoring the 1250 and 87067 . You might be able to use a similar technique.
The most compact expression I can find for the integral is
(87067/1250)*5^((4/25)*ln(2))*exp((2/25)*ln(2)^2+(2/25)*ln(5)^2)
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