[Mauzen]

Quote:

Originally Posted by [MM]IKKE Can you give us the exact question? A tangent is a number (radian), so I don't see how that tangent itself is a radian. What's the context of the question? Have you studied series? If yes, the formula to estimate the Arctan of something is: I converted your angle to radians & filled in the formula, it gives a good result. http://www.wolframalpha.com/input/?i...%3D0.628318531 This is not the solution you posted, so did you post the actual solution or did you post what you THINK is the actual solution? Note that the exact solution matches pi/5, which might be related to something you studies before.

When beginning with trigonometry in school people almost always use degrees. Radians are barely used in school, even in later years. Also, arctan in calculators often offers trigonometric functions for radians and degrees. And thats what he did, arctan 36 in degrees is 88.4. Though I doubt that 36 should be a tangens value, but rather a given angle of the triangle (he also wrote 36°), as i wrote before. A tangens of 36 would be a rather uncommon triangle that rather looks like a line, and teachers stick to common forms to get people used to trigonometry. a 36°/90°/54° triangle would rather be a common form, than a 88.4°/90°/1.6° one.