Let's study "Mathematics" with each other! (6)

1.

If:

 

f(x)=  x  , for x≤1       &      x^2  ,for  x>1

 

Then,

What is the inverse of f(x)?

 

1-    x  , for x≤1       &      √x  ,for  x>1

2-    -x  , for x≤1       &      -√x  ,for  x>1

3-    1/x  , for x≤1       &      1/x^2  ,for  x>1

4-    -1/x  , for x≤1       &      -1/x^2  ,for  x>1

 

 

        *******       *******       *******       *******       *******

 

2.

If:

 

y= ln {(x+1)/(x-1)}

 

Then,

What is the inverse of y?

 

1-    (2e^x-1)/(2e^x+1)

2-    (e^x+1)/(e^x-1)

3-    (e^x-1)/(e^x+1)

4-    (e^x-2)/(e^x+2)

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Replies

  • Solution:

     

    1.

     

    F(2) = 4

     

    Then we must have:

     

    {f(4)}^(-1) = 2

     

    So, only option 1 can be its answer.

     

         *******       *******       *******       *******       *******

     

    2.

     

    y= ln {(x+1)/(x-1)}

    e^y = (x+1)/(x-1)

    e^y (x-1) = (x+1)

    x(e^y) – {(e^y) -1} = x

    x- x(e^y) = -(e^y) -1

    x(1-e^y) = -(e^y) -1

    x = (e^y +1) / (e^y -1)

     

    =>

     

    The answer is:

    y = (e^x+1)/(e^x-1)

    • Geometry!

      Very nice field!!

      Why not!

      Sure.

    • WOW!!

      Sue!

      They are right!!

      You are very smart that can answer them in this condition too!

      Well done dear!

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