Cosh x / sinhx in the form of e^x

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The discussion centers on the definitions of hyperbolic cosine and its properties. The correct formula for cosh(2x) is cosh(2x) = (e^(2x) + e^(-2x)) / 2, not (e^(2x) - e^(-2x)) / 2, which actually corresponds to sinh(2x). Participants emphasize the importance of using parentheses for clarity in expressions involving exponents. There is also a mention of ensuring that reliable sources provide accurate mathematical information. Overall, the conversation clarifies the correct formulation of hyperbolic functions.
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Homework Statement


I was told that coshx = (e^x + e^-x) / 2 , why cosh2x = (e^2x - e^-2x) / 2 ?

Homework Equations

The Attempt at a Solution

 

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goldfish9776 said:

Homework Statement


I was told that coshx = (e^x + e^-x) / 2 , why cosh2x = (e^2x - e^-2x) / 2 ?

Homework Equations

The Attempt at a Solution


Because it is true for any value of x. Any number you can get with x you can get with 2x.
 
If cosh3x then e^x is substituted with e^3x ??
 
goldfish9776 said:
If cosh3x then e^x is substituted with e^3x ??
Yes. Although you really should use parentheses for the expression making up the exponent unless it's written as a superscript.

e^(3x) or e3x .
 
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goldfish9776 said:
I was told that coshx = (e^x + e^-x) / 2 , why cosh2x = (e^2x - e^-2x) / 2 ?
Hi goldfish9776:

I agree that the minus sign in
cosh 2x = (e2x - e-2x) / 2​
is peculiar.
(e2x - e-2x) / 2 = sinh 2x.​

Is the person who told you that
cosh 2x = (e2x - e-2x) / 2​
someone you would expect to be reliable?

Regards,
Buzz
 
@goldfish9776 ,

You have a typo in the OP. The correct statement is:

##\displaystyle \cosh(2x)=\frac{e^{2x}+e^{-2x}}{2} ##
 
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