How to write this expression in terms of a Hyperbolic function?

In summary, to express a mathematical expression using hyperbolic functions, identify the relevant hyperbolic identities, such as sinh(x) = (e^x - e^(-x))/2 and cosh(x) = (e^x + e^(-x))/2. Substitute exponential terms in the expression with the corresponding hyperbolic functions, ensuring that the transformations maintain the equivalence of the expression. Finally, simplify the resulting expression as needed to achieve the desired form.
  • #1
Safinaz
261
8
Homework Statement
How to write this expression in terms of a Hyperbolic function
Relevant Equations
How to write :

##
Eq= e^{t ( -h \pm \sqrt{ x} )}
##

I terms of ##Cosh (x) = e^x + e^{-x} /2 ##
The eqution can be written as:

##
Eq= e^{t( -h + \sqrt{ x} )} + e^{t( -h -\sqrt{ x} )}
##

Can this be written in terms of Cosh x ?
 
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  • #2
It could be written in terms of ##\cosh \sqrt x##.
 
  • #3
PeroK said:
It could be written in terms of ##\cosh \sqrt x##.
So can it written as:

## Eq = e^{ -ht} ( e^{t\sqrt{x}} + e^{-t\sqrt{x}} ) = 2 e^{ -ht} Cosh ( t \sqrt{x}) ##?
 
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  • #4
Safinaz said:
How to write :
##Eq= e^{t ( -h \pm \sqrt{ x} )}##
I presume that represents 2 different 'equations':
##f(t,h,x)= e^{t ( -h + \sqrt{ x} )}## and
##g(t,h,x)= e^{t ( -h - \sqrt{ x} )}##

Safinaz said:
##Cosh (x) = e^x + e^{-x} /2 ##
You are missing brackets and should use a lower case c for ##\cosh##.

Safinaz said:
The eqution can be written as:
##Eq= e^{t( -h + \sqrt{ x} )} + e^{t( -h -\sqrt{ x} )}##
Looks like you are trying to express the two differnt equations as a single equation. That sounds wrong to me. It's a bit like saying ##x = 1 \pm \sqrt 2## and then considering the value of ##(1+\sqrt 2) + (1 -\sqrt 2)## (which is ##2##). It doesn't work.
 
  • #5
Safinaz said:
Can you please write the formula?
It's fairly obvious. I thought the question was to relate that to ##\cosh x##, which I don't think can be simply done.
 
Last edited:
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  • #6
$$2e^{-ht}=\cosh{ht}-\sinh{ht}$$
 
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  • #7
Safinaz said:
Homework Statement: How to write this expression in terms of a Hyperbolic function
Relevant Equations: How to write :

##
Eq= e^{t ( -h \pm \sqrt{ x} )}
##

I terms of ##Cosh (x) = e^x + e^{-x} /2 ##

Is this the question as given to you, or does it represent where you got to in answering some other question? If the latter, please state the original question.
 

FAQ: How to write this expression in terms of a Hyperbolic function?

How do you express exponential functions in terms of hyperbolic functions?

Exponential functions can be expressed in terms of hyperbolic functions using the definitions of hyperbolic sine and cosine. For example, \( e^x \) can be written as \( \cosh(x) + \sinh(x) \), and \( e^{-x} \) can be written as \( \cosh(x) - \sinh(x) \).

How can you write trigonometric functions in terms of hyperbolic functions?

Trigonometric functions can be related to hyperbolic functions through complex arguments. For instance, \( \cos(x) \) can be expressed as \( \cosh(ix) \) and \( \sin(x) \) as \( -i\sinh(ix) \), where \( i \) is the imaginary unit.

What is the relationship between hyperbolic and logarithmic functions?

Hyperbolic functions can be expressed using logarithms. For example, \( \sinh(x) = \frac{e^x - e^{-x}}{2} \) and \( \cosh(x) = \frac{e^x + e^{-x}}{2} \). These can be inverted using logarithmic functions to find \( x \) in terms of \( \sinh(x) \) or \( \cosh(x) \).

How do you convert a polynomial expression to hyperbolic functions?

Converting a polynomial expression to hyperbolic functions generally involves recognizing patterns that match the definitions of hyperbolic sine and cosine. For instance, if you have an expression like \( x^2 - y^2 \), it can be related to \( \cosh^2(z) - \sinh^2(z) = 1 \) for some appropriate variable \( z \).

Can you express inverse hyperbolic functions in terms of logarithms?

Yes, inverse hyperbolic functions can be expressed in terms of logarithms. For example, \( \text{arsinh}(x) = \ln(x + \sqrt{x^2 + 1}) \) and \( \text{arcosh}(x) = \ln(x + \sqrt{x^2 - 1}) \) for \( x \geq 1 \).

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