请教matlab积分怎么积分？？？

i=1:0.01:pi;! i8 k# |# A% ?! f3 T- o
x=1:0.01:pi;
/ P( x$ w& h9 `* [2 d( ON1=13;; U8 `9 Q1 _# [5 \7 a
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N2=15;

for i=1:pi+1+ g/ p- N# M$ A, k* n& ?
   if 0.4*pi+1<=x(i)+1 && x(i)+1<=0.6*pi+1) E/ Y$ v+ |) ]8 K! n' v% V
   phi_2(i)=(N2-N1)*x(i)+1/2;
. o5 d5 B/ T4 T, @$ F& E   end9 b4 w$ T' o" F6 Z% @: \. k* L
    if 0.0*pi+1<=x(i)+1 && x(i)+1<=0.2*pi+1/ g' L1 m0 l1 ?$ }" \6 C6 c
    phi_2(i)=((N2-N1)*x(i)+1+pi)*0.5;& ]' F8 C' Y  Y* N  C( M; ~  N& s
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    end
3 `: }' L% [3 U& K/ C! j) A! wend

syms i;
  q% z# a# D& U' w  F1 SEr=1-abs(exp(1j*(phi_2(i)-((N1+N2)/2)*i)).*cos(((N2-N1)/2)*i-phi_2(i) )).^2;

s=int((Er),0.4*pi,0.6*pi);