Numerical analysis please help

if true
  i=1;
for q=0:0.05:4;
  x(i)=q;
  s(i)=quad('sin(x.^2)',0,x(i));
  c(i)=quad('cos(x.^2)',0,x(i));
  i=i+1;
end
fprintf('\n The value of s(x)=%5.3f',s(i-1))
fprintf('\n The value of c(x)=%5.3f\n',c(i-1))
plot(x,s,x,c)
xlabel('x')
ylabel(' C(x) and S(x)')
grid 
figure
plot(c,s)
xlabel('c'),ylabel('s')

end

[Azzi Abdelmalek]

What is the question?

[francis]

I keep getting the error, please give me some advice on how to approach this

if true
Error in ==> quad at 81
if ~isfinite(y(1))
end

[Mike Hosea]

I got no error. What version of MATLAB are you using?

[Andrew Reibold]

I am using 2012b I believe, and I also received no errors. I did get two sexy looking graphs though.

Answer 1

[dpb]

Replace the loop structure

i=1;
for q=0:0.05:4;
  x(i)=q;
  s(i)=quad('sin(x.^2)',0,x(i));
  c(i)=quad('cos(x.^2)',0,x(i));
  i=i+1;
end

with

q=[0:0.05:4]';
s=accumarray([1:length(q)]',q,[],@(x) quad('sin(x.^2)',0,x));
c=accumarray([1:length(q)]',q,[],@(x) quad('cos(x.^2)',0,x));

If you want to get even more clever, define the functions as function handles... :)

I didn't pursue the initial too much; you should at a minimum preallocate the vectors s and c