Just take a rest from work, type something boring here…
Students, you may regard the above as a formula or derive it by using trigonometric substitution every time.
As you may know that the expression of a primitive is not unique, we may have other forms being a primitive of , say
To show the validity of the above, simply by differentiation (try, esp. the last one). But, apart from the above, any other ‘format’ of a primitive? How to obtain primitives of different ‘formats’ (esp. the last one)?