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Wave Propagation in Linear Media | re-examined

Wave Propagation in Linear Media | re-examined

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In[37]:= f1[x_] := Exp[I (x - 1/x)]/Sqrt[x];<br />

f2[x_] := Exp[I (1/x - x)] Sqrt[x]/x^2;<br />

OscInt[f1,(#-1/#)&,1] + OscInt[f2,(1/#-#)&,1] -<br />

N[(1+I) Sqrt[Pi/2] Exp[-2]]<br />

Out[37]= -13 -13<br />

9.02889 10 + 2.14218 10 I<br />

7 Mathematica implementation of a quadratu<strong>re</strong> function<br />

Instead of us<strong>in</strong>g the exact argument functions x , 1=x and 1=x , x to determ<strong>in</strong>e the partition po<strong>in</strong>ts<br />

we could as well take their polynomial parts x and ,x, <strong>re</strong>spectively, which yields even slightly better<br />

<strong>re</strong>sults.<br />

In[38]:= OscInt[f1,#&,1] + OscInt[f2,-#&,1] -<br />

N[(1+I) Sqrt[Pi/2] Exp[-2]]<br />

Out[38]= -15 -14<br />

2.52576 10 + 3.71925 10 I<br />

Example 7.5.18<br />

Z 1<br />

0<br />

s<strong>in</strong> 3 x<br />

x 2<br />

In[39]:= f[x_] := S<strong>in</strong>[x]^3/x^2;<br />

OscInt[f,#&,0] - N[3/4 Log[3]]<br />

Out[39]= -14<br />

-7.39409 10<br />

Example 7.5.19<br />

Z 1<br />

0<br />

s<strong>in</strong> x , x cos x<br />

x 3<br />

In[40]:= f[x_] := (S<strong>in</strong>[x] - x Cos[x])/x^3;<br />

OscInt[f,#&,0] - N[Pi/4]<br />

Out[40]= -13<br />

-2.498 10<br />

Example 7.5.20<br />

Z 1<br />

0<br />

s<strong>in</strong> x 2 , 1<br />

x 2<br />

dx = 3<br />

ln 3<br />

4<br />

dx = 4<br />

dx = 1<br />

r<br />

2 2 e,2<br />

Divid<strong>in</strong>g the range of <strong>in</strong>tegration and with the change of variable x2 ! 1=x2 , we obta<strong>in</strong> the two<br />

2 dx<br />

<strong>in</strong>tegrals R 1<br />

1 s<strong>in</strong> , x 2 , 1<br />

x 2<br />

dx and R 1<br />

1 s<strong>in</strong> , 1<br />

x 2 , x<br />

188<br />

x 2 , <strong>re</strong>spectively.

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