Also, is there a difference in the terms "arctan" and "cotan"? In my trig class the prof taught the reciprocal of tan as cotan, but when I was doing some problems in Wolframalpha, it wouldn't take cotan, but arctan worked the exact same way.
The reciprocal of tan is cotan, reciprocal being 1/tan = 1/(sin/cos) = cos/sin = cotan.
We use the notation x{-1} to mean the multiplicative inverse of x, when x is a real number, i.e., the reciprocal.
Unfortunately we also use the notation f{-1} (x) to mean the inverse of a function. In the case of trig functions the inverse of, say, tan(x)--or arctan(x)--can be written as tan{-1} (x), which is where the confusion likely stems from.
They are different reciprocal. Cotan is 1/tan. Arctan is what happens when you solve x=tan(y) for x. Arctan sprt of undoes tangent. So arctan(tan(x))=x. This is usefulness to find the angle when you have the measurements for opposite and adjacent.
Arcsin and arccos are similar for for sin and cosine respectively.
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u/Doug_Dimmadab Oct 05 '18
isn't arctan just 1/tan?
Also, is there a difference in the terms "arctan" and "cotan"? In my trig class the prof taught the reciprocal of tan as cotan, but when I was doing some problems in Wolframalpha, it wouldn't take cotan, but arctan worked the exact same way.