Show that is increasing in R.

Given:


To show: the given function is increasing in R.


Explanation: Given


Applying first derivative with respect to x, we get




But the derivative of 2x is 2, so



But the derivative of , so




Applying the sum rule to last part we get










cancelling the like terms, we get



Now adding by taking the LCM, we get




Now for any real value of x, the above value of f(x) is greater than or equal to zero


Hence


And we know, if f’(x)≥0, then f(x) is increasing function.


Hence the given function is increasing function in R.


20