# How do you calculate the derivative of #intsqrt(1+ sec(t)) dt# from #[x, pi]#?

##### 1 Answer

#### Answer:

I would call this a trick question. Although, like many so-called trick questions, it may just be a test of out attention to detail. (Or an oversight by the examiner.)

#### Explanation:

Observe that

**However!**

For

If we are working in the real number system (as first calculus classes do), then:

The domain of:

is the singleton

There is no derivative of such a function.

**How does this kind of question happen?**

Either the examiner wanted to make sure that students check the condition for using the fundamental theorem before trying to apply it, or, in a rush to write a question, the examiner inadvertently wrote an unintended question.