[djpailo]

Does anyone know where the "arc hyperbolic functions" are found on a calculator, such as arcsech, arccosech and arccoth.

My calculator is the standard Casio calculator you buy off the shelf, has "fx 83ES".

[Hasufel]

most calculators don`t have these functions (unless the cost upwards of £50 or something like that) - i have 2 really good `uns and they don`t!

you could just try graphing their logarithmic equivalents -

e.g Arcsinh(x) = Ln(x+Sqrt(x^2+1))...etc.

[Contrad!ction.]

If it was going to be anywhere, it'd be on the 'hyp' button. I have the PLUS version of that calculator, and to get those, you whack 'hyp', one of the grey (as opposed to black) buttons, and select 4, 5 or 6. If you want the flipped hyperbolics, then you'll have to use 1/x instead of x, and use, say, sinh instead of cosech.

However, you could do them manually eg , and so on. Chances are, you'll have to write them in exact form anyway.

[Intriguing Alias]

(Original post by djpailo)
Does anyone know where the "arc hyperbolic functions" are found on a calculator, such as arcsech, arccosech and arccoth.

My calculator is the standard Casio calculator you buy off the shelf, has "fx 83ES".

(Original post by Contrad!ction.)
If it was going to be anywhere, it'd be on the 'hyp' button. And yeah, if my 991ES Plus doesn't do it, then yours won't.

However, you could do them manually eg , and so on. Chances are, you'll have to write them in exact form anyway.

My fx-85GT PLUS does indeed have cosh^-1, sinh^-1 and tanh^-1 via the hyp button.

And OP it's actually ar*insert hyp function here* not arc as they denote areas of sectors, not arc lengths of sectors.

Ooh and congratulations on becoming a mod, Contrad!ction

[Contrad!ction.]

(Original post by hassi94)
My fx-85GT PLUS does indeed have cosh^-1, sinh^-1 and tanh^-1 via the hyp button.

And OP it's actually ar*insert hyp function here* not arc as they denote areas of sectors, not arc lengths of sectors.

Ooh and congratulations on becoming a mod, Contrad!ction

I'm being a plonker, actually. For some reason it wasn't registering in my brain - both my 991ES PLUS and my 83GT PLUS have got the ^-1s.

...no cosech/coth/sech though.

Haha, cheers

OP - anyway, the formulae might still be useful if you have to quote exact values.

[Intriguing Alias]

(Original post by Contrad!ction.)
OP - anyway, the formulae might still be useful if you have to quote exact values.

Definitely; though they should be in the formula booklet (at least they are for AQA)

I don't think I've ever come across a question where I needed to use my calculator hyp functions though to be honest. Could help for checking I guess?

[djpailo]

(Original post by Contrad!ction.)
If it was going to be anywhere, it'd be on the 'hyp' button. I have the PLUS version of that calculator, and to get those, you whack 'hyp', one of the grey (as opposed to black) buttons, and select 4, 5 or 6. If you want the flipped hyperbolics, then you'll have to use 1/x instead of x, and use, say, sinh instead of cosech.

However, you could do them manually eg , and so on. Chances are, you'll have to write them in exact form anyway.

Yes, I think it might be easier using exact. Do you know where I can find a full list of all these exact forms etc?

(Original post by hassi94)
My fx-85GT PLUS does indeed have cosh^-1, sinh^-1 and tanh^-1 via the hyp button.

And OP it's actually ar*insert hyp function here* not arc as they denote areas of sectors, not arc lengths of sectors.

Ooh and congratulations on becoming a mod, Contrad!ction

Thanks for the info, never knew that!

[Intriguing Alias]

(Original post by djpailo)
Yes, I think it might be easier using exact. Do you know where I can find a full list of all these exact forms etc?

Should be in your formula book, if not however:

http://en.wikipedia.org/wiki/Inverse...bolic_function

[Contrad!ction.]

(Original post by djpailo)
Yes, I think it might be easier using exact. Do you know where I can find a full list of all these exact forms etc?




Thanks for the info, never knew that!

They're likely to be in your exam board's formula book. If OCR, it's page 3. They give you sinh, cosh and tanh, so you'll need to use 1/x for the 1/ functions.

Alternatively:

[djpailo]

(Original post by hassi94)
Should be in your formula book, if not however:

http://en.wikipedia.org/wiki/Inverse...bolic_function

Thanks!

I'm in university and I don't think we get given anything (tbh not sure and he hasn't mentioned anything). We are doing bifurcations and graphically solving where the bifurcation occurs for lamda:

x dot = x + tanh(lambda*x)

where lamda is any constant.

[djpailo]

It basically came down to solving this:



But I dunno how he got Lambda = -1 and still can't do it even with using the exact identities

[Intriguing Alias]

(Original post by djpailo)
It basically came down to solving this:



But I dunno how he got Lambda = -1 and still can't do it even with using the exact identities

I don't know how we can show this just using the logarithmic form to be honest. I don't even think it's possible. It's probably something to do with bifurcations but I'm sorry I don't know anything about that - I'm only doing A-levels. Maybe posting a new thread would help?