# Not able to solve this expression

1 view (last 30 days)
Anshuman S on 10 Oct 2018
Commented: KALYAN ACHARJYA on 10 Oct 2018 I am not able to code this expression , I have tried but it's not giving correct answer ! My try is given below:
if true
sol= zeros(4,4);
s=0;
for i = 1:5
for j = 1:5
r = (j-1)*0.25 ;
fi = 2*pi*(i-1)/4 ;
disp(r)
disp(fi)
disp('r,fi')
for m1 =1:100000
s = s + (2*((r/0.03)^(2*m1))*cos(2*m1*fi)) / ((4*m1*m1 - 1)*(1 + (2*m1*40)/(20*0.03)));
end
sol(i,j)= 1/pi - (1/pi)*s + ((r/0.03)*sin(fi))/(2*(1+ (45/(20*0.03))));
end
end
disp(sol)
end
The r & phi are taken for 5 and 5 points respectively . r = 0, 0,25, 0,50, 0,75 1.0 and simillarly phi = 0, pi/2 , pi , 3pi/2 , 2pi . But my solution is coming very large than the expected value.

Show 1 older comment
Anshuman S on 10 Oct 2018
It must come in some real number , as Q(Theta) is non dimmensionalised it won't be to much in magnitude, may be less than 100 only . Thus each value coming in range of 1 to 100. ( or something close to that only )
madhan ravi on 10 Oct 2018
" for m1 =1:100000 aftermath due to this leads to more values "
Anshuman S on 10 Oct 2018
it's given in the problem to take many number of terms, m1 shows the number of terms in the series, in the problem it's taken to be infinite

Anshuman S on 10 Oct 2018
I have solved the problem now , The r term was not within the bounds. It should be less than r0 ( 0.03 cm ) . thus r = 0.03*(j-1)*0.25 ;
Thanks for your time and help !

#### 1 Comment

KALYAN ACHARJYA on 10 Oct 2018
Great Bravo!