Question

Why we used to write angles in radians as we can also write them in degree?

It should be fully explained bookish language is not considered.​

Answer 1

Answer:

Radians are not units; they are dimensionless, just like any other number. So, at the high school level it’s OK to write pi radians, but that doesn’t really make much sense… For example, if we started writing pi radians, then Euler’s formula would be exp(i pi radians) + 1 = 0. But then for consistency we’d have to write exp(0 radians) = 1, which looks quite silly because 0 is just a number. And pi is just a number. By contrast, “degrees” are units, like feet, meters, seconds, and grams.