Talk:Trigonometry/Radians

Suitability for those new-to-Radians
This page in its current form is unsuitable for anyone new to radians. It does not explain why we would want to use radians (admittedly a difficult sell at this stage, with no calculus). Also I have never seen the crazy $$\displaystyle\theta^c$$ notation. JamesCrook (talk) 21:04, 27 October 2010 (UTC)

Picture is wrong
It is obvious that the picture of an angle of 1 radian doesn't really show a 1 radian angle.130.89.219.179 15:46, 5 October 2005 (UTC)

Keeping the Units Right
I changed the formulas for converting, because I didn't understand them. Let's look at an example:


 * $$\theta=60^\circ$$

Now converting, using the original formula:


 * $$\theta^\circ \frac {\pi}{180}=(60^\circ)^\circ \frac {\pi}{180} = (\frac {\pi}{30})^{\circ\circ}$$

Let's try it another way:


 * $$\alpha =\theta^\circ = 60^\circ$$

Converting:


 * $$\theta^\circ \frac {\pi}{180}=60^\circ \frac {\pi}{180} = (\frac {\pi}{30})^\circ$$

The answer is in degrees!?

Now suppose the answer should be the number of radians. What is the meaning of the degree symbol in the formula?

130.89.219.179 16:25, 5 October 2005 (UTC)

When you changed 60 degrees to radians, your formula was wrong. The part:

Theta*pi/180

is wrong. It is supposed to be

Theta*pi/180°, so that the degree symbol is eliminated.

Correcting your equation,

Theta*pi/180°=60° *pi/180°=pi/30

Centesimal system
The principal unit in system is grade and is denoted by (g).One right angle is divided in 100 equal parts,called grades,and each grade is subdivided into 100 minutes,and each minutes,and each minutes into 100 seconds.

IN MATHEMATICAL FORM : ONE RIGHT ANGLE = 100grade 1 grade = 100' 1'     = 100".