Trying to find an inverse equation - maybe cosh/sinh

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In summary, the conversation discussed finding the inverse of the function f(t) = \frac{2e^{t} + 3e^{-t}}{e^{t} + 2e^{-t}}. The method suggested was to swap the variables t and x and solve for x, resulting in x = ln\sqrt{\frac{3-2t}{t-2}}. This would give the inverse function f^{-1}(t).
  • #1
meee
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Given [tex]f(t) =[/tex] [tex]\frac{2e^{t} + 3e^{-t}}{e^{t} + 2e^{-t}}[/tex] find [tex]f^{-1}(t)[/tex]My attempt:
i worked for about half an hour but i think I am not doing the right thing. i tried multiplying it out, factorizing, pretty much just playing around with it.
OMMGG mayb got it
 
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  • #2
I would do this: write the equation as
[tex]x= \frac{2e^t+ 3e^{-t}}{e^t+ 2e^{-t}}[/tex]
Now swap x and t:
[tex]t= \frac{2e^x+ 3e^{-x}}{e^x+ 2e^{-x}}[/tex]
That "gives" the inverse function. Now you "only" have to solve for x!

Multiply that denominator on both sides:
[tex]te^x+ 2te^{-x}= 2e^x+ 3e^{-x}[/tex]
Multiply the entire equation by ex
[tex]te^{2x}+ 2t= 2e^{2x}+ 3[/tex]
Let y= e^x so that you get a quadratic in y
[tex]ty^2+ 2t= 2y^2+ 3[/tex]
Solve that by a simple square root, then take ln of both sides to find x as a function of x.
 
  • #3
ooooohh thankszzz
sooo [tex] x = ln\sqrt{\frac{3-2t}{t-2}}[/tex]
 

What is an inverse equation?

An inverse equation is a mathematical relationship between two variables where one variable can be expressed as a function of the other. In other words, it is a way to find the original input value given the output value.

Why is finding an inverse equation important?

Finding an inverse equation is important because it allows us to solve problems in reverse. It helps us understand the relationship between variables and can be used to make predictions or solve equations that would otherwise be difficult to solve.

What is the process for finding an inverse equation?

The process for finding an inverse equation involves isolating the dependent variable and switching the independent and dependent variables. This can be done by using algebraic manipulation and/or graphing techniques.

What is the inverse equation for cosh?

The inverse equation for cosh is arccosh, also known as hyperbolic cosine inverse. It is written as arccosh(x) and is the inverse function of cosh(x).

Is there an inverse equation for sinh?

Yes, there is an inverse equation for sinh. It is called arcsinh, or hyperbolic sine inverse, and is written as arcsinh(x). It is the inverse function of sinh(x).

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