need a little help here

[HarisShahzad]

Im appearing in add maths exam TODAY and i dont know how to find out the inverse of an absoulute function ???

 

[Diishiik Douw]

Example:
f : x ----> 5x - 2

Find F^ (-1)

Let F(x) = y

y= 5x - 2

make x subject of formula.

y + 2 = 5x

x = ( y + 2 ) / 5


nOw : F ^ (-1) : [replace y be x)

= (x+2) / 5

 

[HarisShahzad]

thnx for your help bro but im talking about an absolute function as in f(X)=|2x-3|-4

 

[Diishiik Douw]

i'm a girl

wait..


'll just do it

 

[HarisShahzad]

oooooooooh, sorry about that

 

[Diishiik Douw]

y = |2x-3| - 4
A modulus can be +ve oR -ve

-y = (2x - 3) - 4 Or y= -(2x-3) -4
make X subject of formula in both cases ,u'll have the following

x = (7-y)/2 and x = -(y+1)/2

switch the places of x and y..

the answer will be

F^-1 (x) = (7 - x )/2
and -(x+1)/2

 

[HarisShahzad]

okie thnx