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diff --git a/2378/CH1/EX1.18/Exa_1_18.png b/2378/CH1/EX1.18/Exa_1_18.png
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diff --git a/2378/CH1/EX1.18/Exa_1_18.sce b/2378/CH1/EX1.18/Exa_1_18.sce
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+//numerical fourier analysis (note:this example is same as Exa_1_13)
+//Exa_1_18
+clc;
+clear;
+close;
+
+n=12;
+        //number of time stations
+m=5;
+        //number of harmonics required
+time=0.12;        //time period
+
+x=[20000.0;34000.0;42000.0;49000.0;53000.0;70000.0;60000.0;36000.0;22000.0;
+   16000.0;7000.0;0.0]';
+        //presure in N/m^2
+t=0.01:0.01:0.12;        //time in second
+
+sumz=0.0;
+        //temporary variable
+for i=1:n        //calculating the coefficients
+   sumz=sumz+x(i);
+end
+azero=2.0*sumz/n;
+        //first term of fourier series  
+for ii=1:m
+   sums=0.0;
+   sumc=0.0;
+   for i=1:n
+      theta=2.0*%pi*t(i)*ii/time;
+      coss(i)=x(i)*cos(theta);
+      sinn(i)=x(i)*sin(theta);
+      sums=sums+sinn(i);
+      sumc=sumc+coss(i);
+   end
+   a(ii)=2.0*sumc/n;
+        //coefficient of cos terms
+   b(ii)=2.0*sums/n;        //coefficient of sin term
+
+end
+
+
+//printing the table of values
+printf('Fourier series expansion of the function x(t)\n\n');
+printf('Data:\n\n');
+printf('Number of data points in one cycle = %3.0f \n',n);
+printf(' \n');
+printf('Number of Fourier Coefficients required = %3.0f \n',m);
+printf(' \n');
+printf('Time period = %8.6e \n\n',time);
+printf('Station i       ')
+printf('Time at station i: t(i)         ')
+printf('x(i) at t(i)')
+for i=1:12
+   printf('\n %8d%25.6e%27.6e ',i,t(i),x(i));
+end
+printf(' \n\n');
+printf('Results of Fourier analysis:\n\n');
+printf('azero=%8.6e \n\n',azero);
+printf('values of i       a(i)                b(i)\n');
+for i=1:5
+   printf('%10.0g   %8.6e%20.6e \n',i,a(i),b(i));
+end
+
+   
+\ No newline at end of file