HP 35s Scientific Calculator - Manual (Page 150)

9-8 Operations with Complex Numbers
Complex Number in Program
In a program, you can type a complex number. For example, 1i2+3
θ
10+5
θ
30 in program is:
When you are running a program and are prompted for values by INPUT
instructions, you can enter complex numbers. The values and format of the result
are controlled by the display setting.
The program that contains the complex number can also be solved and integrated.
Program lines: (ALG mode) Description
   Begins the program
      
 