Talk:Trigonometric Substitutions

The statement (sin theta)= sqrt(a^2 - x^2) is not true, as far as I can understand. This would mean sin theta is a length. The similar statements for tangent and secant are also untrue. If the parentheses are supposed to indicate something which makes the statement true, then it is not obvious. I am a physics major in my 3rd year at Vanderbilt, and I'm quite confused at what the author meant to teach 129.59.115.1 21:27, 26 August 2012 (UTC)