# The sine integral function: Si

### 5.8.8 The sine integral function: Si

The sine integral function is defined by

Si(x) =

∫

x
0

sin(t)
t

dt

and Si(0) = 0, Si(−∞) = −π/2 and Si(+∞) = π/2. Note that Si is an odd function.

The Si command computes the sine integral function.

- Si command takes one argument:
  z, a complex number.
- Si(z) returns the value of the sine integral function Si(z).

#### Example.

Input:

Si(1.0)

Output:

0.946083070367

Input:

Si(-1.0)

Output:

−0.946083070367