As someone who studied electricity, you will be confused with the imaginary calculations such as: (30 + j25) × (40 ∟ 65°). Two models number in parentheses is a complex numbers, where 30 + j25 is call rectangular form and 40 ∟ 65° is call polar form.
Rectangular form is a number that can be put in the form x + jy, where x and y are real numbers and j is called the imaginary unit. In this expression, x is called the real part and y the imaginary part of the complex number.
Polar form is a number that can be put in the form r ∟ φ°, where r is absolute value and φ is angle value. Together, r and φ give another way of representing complex numbers.
To solve the above calculations problem, you should have a scientific calculator, and you should know how to operate it. Can you do it? And to make it easier I will give complex numbers conversion software, free for you.
Download at Google code here ★ Converting complex numbers ★. Download and save rar file (size 10.4 kB), extract and run, as shown below