Trigonometry quetion

[macdreboi]

Hey guys I am new in this forum so if i posted this question in the wrong section, please notify me. Anyway.
My concern here is this.

So I am trying to find the RATE OF CHANGE of f from pi to 11pi/6

f(x)= tan x

I have attached the part i need help on.
Note: This is very simple but there is one step which i don't understand.

The part where 11pi/6 - pi = 5pi/6 <----- How is this? Please explain.....
thanks in advance.

[SteamKing]

Don't you know how to add and subtract fractions?

[quietrain]

the question is as good as asking you to find the gradient,

so the '11pi/6 - pi = 5pi/6' part is the x value of the gradient.,

similarly, the y value of the gradient is the top part as shown in your question

gradient is

y1 - y0
--------
x1 - x0

[HallsofIvy]

Hey guys I am new in this forum so if i posted this question in the wrong section, please notify me. Anyway.
My concern here is this.

So I am trying to find the RATE OF CHANGE of f from pi to 11pi/6

f(x)= tan x

I have attached the part i need help on.
Note: This is very simple but there is one step which i don't understand.

The part where 11pi/6 - pi = 5pi/6 <----- How is this? Please explain.....
thanks in advance.
11pi/6- pi= pi(11/6- 1)= pi(11/6- 6/6).