### Related

##### hankel_1

hankel_1(2/3,0.5);

Calculate

##### hankel_1

hankel_1(2/3,0.5);

hankel_1(2/5,0.5);

Calculate

? hankel_1;

Calculate

hankel_1(1,0.5);

Calculate

##### hankel_1

hankel_1(2/3,0.5);

Calculate

##### hankel_1

hankel_1(2/3,0.5);

hankel_1(2/5,0.5);

Calculate

? hankel_1;

Calculate

hankel_1(1,0.5);

Calculate

### hankel_1

Run Example
```(%i1)hankel_1(1,0.5);
(%o1)               0.24226845767487 - 1.471472392670243 %i
(%i2) ```
Run Example
```fn(x,N) := sin(x) + sum((-1)^i*cos(x),i,0,N);
i
(%o1)          fn(x, N) := sin(x) + sum((- 1)  cos(x), i, 0, N)
(%i2) plot2d(fn(x,10),[x,0,%pi *2]);
plotkso(ka,N) := 4 * abs(bessel_j(0,ka)/hankel_1(0,ka) + 2*sum( ((-1)^n*bessel_j(n,ka)/hankel_1(n,ka)),n,1,N))^2;
(%o3) kso(ka, N) := 4
2
!                             n                          !
!bessel_j(0, ka)         (- 1)  bessel_j(n, ka)          !
!--------------- + 2 sum(----------------------, n, 1, N)!
!hankel_1(0, ka)            hankel_1(n, ka)              !
(%i4) ```
Run Example
```kso(ka,N) := 4 * abs(bessel_j(0,ka)/abs(hankel_1(0,ka)) + 2*sum( ((-1)^n*bessel_j(n,ka)/abs(hankel_1(n,ka))),n,1,N))^2;
(%o1) kso(ka, N) := 4
2
!                                  n                          !
!  bessel_j(0, ka)            (- 1)  bessel_j(n, ka)          !
!-------------------- + 2 sum(----------------------, n, 1, N)!
!abs(hankel_1(0, ka))          abs(hankel_1(n, ka))           !
(%i2) plot2d(kso(ka,14), [ka,0.0,8.0]);
plot```

### Related Help

Help for Hankel_1