Add all the A tasks

Task/Arithmetic-Complex/Go/arithmetic-complex.go

@@ -0,0 +1,18 @@
+package main
+
+import (
+    "fmt"
+    "math/cmplx"
+)
+
+func main() {
+    a := 1 + 1i
+    b := 3.14159 + 1.25i
+    fmt.Println("a:      ", a)
+    fmt.Println("b:      ", b)
+    fmt.Println("a + b:  ", a+b)
+    fmt.Println("a * b:  ", a*b)
+    fmt.Println("-a:     ", -a)
+    fmt.Println("1 / a:  ", 1/a)
+    fmt.Println("a̅:      ", cmplx.Conj(a))
+}