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hHow do I reverse this formular?

y = 1.029x + 2.25

 May 7, 2015

Best Answer 

 #1
avatar+130511 
+5

 

 

I assume you want the "inverse" of this  ???

y = 1.029^x + 2.25   subtract 2.25 from both sides

y - 2.25  = 1.029^x    take the log of both sides

log [ y - 2.25] = log 1.029^x     and we can write

log [ y - 2.25 ] = x log 1.029     divide both sides by log1.029

log [ y - 2.25 ] / log 1.029  = x    "exchange" x and y

log [ x - 2.25 ] / log 1.029   = y    and for y, we can write  f-1(x)

So the inverse is

 f-1(x)  = log [ x - 2.25 ] / log 1.029

 

Here's the graph of both.....https://www.desmos.com/calculator/zjdmsqygfg

Notice that the graph is symmetric to y = x.....as we would expect....

 

  

 May 7, 2015
 #1
avatar+130511 
+5
Best Answer

 

 

I assume you want the "inverse" of this  ???

y = 1.029^x + 2.25   subtract 2.25 from both sides

y - 2.25  = 1.029^x    take the log of both sides

log [ y - 2.25] = log 1.029^x     and we can write

log [ y - 2.25 ] = x log 1.029     divide both sides by log1.029

log [ y - 2.25 ] / log 1.029  = x    "exchange" x and y

log [ x - 2.25 ] / log 1.029   = y    and for y, we can write  f-1(x)

So the inverse is

 f-1(x)  = log [ x - 2.25 ] / log 1.029

 

Here's the graph of both.....https://www.desmos.com/calculator/zjdmsqygfg

Notice that the graph is symmetric to y = x.....as we would expect....

 

  

CPhill May 7, 2015

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