Where is the absolute value when computing antiderivatives?
Here is a typical second-semester single-variable calculus question:
Students are probably taught to just memorize the result of this since the derivative of arcsin(x) is taught as a rule to memorize. However, if we were to actually try and find an antiderivative, we might let
so the integral may be rewritten as
At this point, students then simplify the denominator to just , which boils the integral down to
which is the correct antiderivative. However, by definition, , implying that the integral above should really be simplified to depending on the interval for . At this point, it looks like the answer that we will eventually arrive at is different from what we know the correct answer to be.