Hi 
I  have this equation
Z = pi*a*rho*c*(R1*(2ka) + jX1(2ka)).........(1)
where 
R1(x) = 1- 2*J1(x)/x      J1 is bessel function of first order   
and   x= 2ka
also X1(x) = 2H1(x)/x
H1 is struve function
 
H1(x) = 2/pi - Jo(x) + (16/pi-5)sinx/x + (12-36/pi)(1-cosx)/x^2

also R1(x) in power series is 
R1(x) = (x^2/2.4 - x^4/2.4^2.6 + x^6/2.4^2.6^2.8 ...)
in power series 
X1(x)=2H1(x)/x= 4/pi(x/3 - x^3/3^2.5 + x^5/3^2.5^2.7+...)
	Now I want to plot the real and imaginary parts of eq1 on loglog 
scale vs ka  normalized to pi*a*rho*c

how I take bessel function and struve function in play for ploting 
I guess powers eries has some thing to do with it but I am unable to 
get it work
Help with the coding