what formula do i use to find the average rate of change

[gloomy monolith]

(f(4)-f(1)/4-1

[old jacinth]

just to make sure, it is not this?

[gloomy monolith]

uh yeah

you might be able to use that

but i use what i said

[old jacinth]

i tried putting both formulas into mathway and it gave me different answers,

and neither of them matched the answer it gave me when i put in f(x)=ln3x 1<=x<=4

so i am confused about that

[gloomy monolith]

you want to find the rate of change right?/

[old jacinth]

ya

[gloomy monolith]

its just the slope formula

[gloomy monolith]

i literally dont know what this is

[old jacinth]

me neither

so in the equation it says f(x)=ln3x

does 3x have a role in the formula u gave me?

[gloomy monolith]

yeah f(x)=ln(3x)

[old jacinth]

do i do f(1)=ln(3(1)) and f(4)=ln(3(4)), and then do f(b)-f(a) / x2-x1

?

btw, i know how to find the derivative of a function on a given interval, but i do not know how ln works

if that makes things any easier

[gloomy monolith]

yeah except f(b)-f(a) and x2=b and x1=a

[gloomy monolith]

you dont need derivitives for this im pretty sure

[summer flint]

Basically ln is log_e

[old jacinth]

idk what log_e is

[summer flint]

_ means subscript so normally log means log_10 but ln is log_e
the log functions are a way to calculate the exponent of an equation so y=e^x can be shown as x=ln(y)
Or y=10^x can be shown as x=log(y)