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How do i find a formula for the inverse if this is one to one

x-10/x+4

 Jul 31, 2016
 #1
avatar+14986 
0

Good evening Guest!

 

How do i find a formula for the inverse

if this is one to one x - 10 /x + 4

 

y = x - \(\frac{10}{x} \) + 4

 

Inverse

x = y - \(\frac{10}{y} \) + 4

xy = y² - 10 + 4y

y² - 10 + 4y - xy = 0

y² + (4 - x) y - 10 = 0

 

Quadratic formula

\(y = {-b \pm \sqrt{b^2-4ac} \over 2a}\)

 

a = 1   b = (4 - x)    c = - 10

 

\(y = {x-4 \pm \sqrt{(4-x)^2+40} \over 2}\)  

This is the inverse function.

 

Greetings asinus :- )

 laugh !

 Jul 31, 2016
 #2
avatar+9665 
0

Further steps on asinus's last step.

 

\(\huge\color{blue}y=\dfrac{x-4\pm\sqrt{(4-x)^2+40}}{2}\)

Oops is it too big xD

\(\huge\color{blue}y=\dfrac{x-4\pm\sqrt{-x^2+8x+24}}{2}\)

MaxWong  Aug 1, 2016
 #3
avatar+14986 
0

Hello max, so it's true.


\(y= \frac{x- 4\pm \sqrt{x^{2}- 8x+ 56 } }{2}\)

asinus  Aug 1, 2016
 #4
avatar+9665 
0

Oops I was wrong in the last bit :P

MaxWong  Aug 1, 2016

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