Complex Number Calculator

This works with complex numbers in both of the forms they are usually written in. Enter two numbers as a + bi and pick an operation, or enter one and get its modulus, argument, conjugate, reciprocal and polar and exponential forms; a separate action turns a modulus and an angle back into a + bi. Powers are taken by repeated multiplication, which stays exact for whole-number inputs, with the De Moivre quantities printed beside the answer, and the roots action lists all n of the nth roots with the angle between them. Arguments come back as the principal value from atan2, so they run from -180 to 180 degrees rather than 0 to 360. Every part is rounded to 10 decimal places before printing, because the cosine of a right angle is not exactly zero in binary.