# Angles - why in radians instead of in degrees?

1. Jul 6, 2012

### amaresh92

angles -- why in radians instead of in degrees?

greetings,

why all the angle in electrical is represented in radian instead in degree?
advanced thanks

2. Jul 6, 2012

### Staff: Mentor

Re: angles -- why in radians instead of in degrees?

Radians are more natural is solving various electrical problems. Wikipedia has some discussion on its advantages.

http://en.wikipedia.org/wiki/Radian

3. Jul 6, 2012

### Staff: Mentor

Re: angles -- why in radians instead of in degrees?

Can you think of some reasons? What kind of equations do we typically use in EE?

4. Jul 6, 2012

### Staff: Mentor

Re: angles -- why in radians instead of in degrees?

It makes for simpler equations,
e.g., the arc length of a circle segment = r.θ

5. Jul 7, 2012

### amaresh92

Re: angles -- why in radians instead of in degrees?

equations normally involves both magnitude and phase.

6. Jul 7, 2012

### sophiecentaur

Re: angles -- why in radians instead of in degrees?

It seems quite arbitrary until you look into the basic principles of differentiation. You are looking to find the slope of a curve, a sine wave say, by making a small triangle and working out the lengths of the sides. Then you find the value as the triangle size approaches zero. The simple answer that d(Sin θ)/dθ = Cos θ relies on using radians to measure that angle.
"www.mash.dept.shef.ac.uk/Resources/sincosfirstprinciples.pdf" [Broken] presents it more or less as I remember being taught in medieval times by dear old Mr Worthington. Half way through, they make the point that the angle is in radians. If you don't measure the angle in radians, every time you differentiate or integrate a trig function, you get a bizarre constant, depending on which angle units you chose.
The inhabitants of Planet Zog, who use 413 zogdegrees in their circles will also be using radians and not zogdegrees for this reason.

Last edited by a moderator: May 6, 2017
7. Jul 7, 2012

### psparky

Re: angles -- why in radians instead of in degrees?

If they didn't use both angles and radians.....they wouldn't have anything to test you on in school...lol

Seriously, you need to be able to "snap" back and forth from angles to radians and then snap over to frequency...then snap over to the period. You will always be going back and forth between these things. Learn them now and embrace them. They all have their purposes.

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook