I'm trying to solve the question for f(x)= x + sin x find the average rate of change of f(x) for

i) [0, pi / 2]

I think the formula is f(b)-f(a) / b-a

in which this case we would have

pi/2 + sin pi/2 - sin0 / pi/2 - 0

I'm not sure if I got this right though.

Edit: Okay so I got my formula:

change over y / change over x

f(x2) - f(x1) / fx2 - fx1

In the above scenario I think we have to factor out something to eliminate the denominator but I'm not sure how to do it.