1. The problem statement, all variables and given/known data Evaluate the definite (from -0.3 to 0.3) integral ∫tanxdx 2. Relevant equations (dy/dx)tanx=(secx)^2 3. The attempt at a solution Using the anti-derivative, I got to (sec(0.3))^2-(sec(-0.3))^2, which gives approximately 2. However, if the derivative is sketched out, and the area underneath is found, the answer is then 0. I found this happening with other similar questions as well. What could be going on?