# Differentiating tanh [Solved!]

**Haida** 26 Nov 2015, 08:13

### My question

what the answer if we differentiate `y = tanh (x-9)`?

### Relevant page

Differentiation of Transcendental Functions

### What I've done so far

I tried to find this on IntMath, but couldn't.

X

what the answer if we differentiate `y = tanh (x-9)`?

Relevant page
<a href="/differentiation-transcendental/differentiate-transcendental-intro.php">Differentiation of Transcendental Functions</a>
What I've done so far
I tried to find this on IntMath, but couldn't.

## Re: Differentiating tanh

**Murray** 26 Nov 2015, 16:36

Hello Haida

This is not "`tan`", but `"tanh`".

IntMath doesn't include the hyperbolic functions (yet), but you can see the formula for differentiating `tanh x` at:

Table of Derivatives

Your situation is a function of function situation. Do you think you can do it now?

Good luck with it.

Regards

M Bourne

X

Hello Haida
This is not "`tan`", but `"tanh`".
IntMath doesn't include the hyperbolic functions (yet), but you can see the formula for differentiating `tanh x` at:
<a href="/differentiation-transcendental/table-derivatives.php">Table of Derivatives</a>
Your situation is a function of function situation. Do you think you can do it now?
Good luck with it.
Regards
M Bourne

## Re: Differentiating tanh

**Haida** 27 Nov 2015, 13:38

I think it's

Put `u=x-9` so `y= tanh u`.

Then `dy/dx = dy/(du) (du)/dx`

` = (1-tanh^2 u)(du)/dx = 1 - tanh^2(x-9)`.

Is it OK?

X

I think it's
Put `u=x-9` so `y= tanh u`.
Then `dy/dx = dy/(du) (du)/dx`
` = (1-tanh^2 u)(du)/dx = 1 - tanh^2(x-9)`.
Is it OK?

## Re: Differentiating tanh

**Murray** 28 Nov 2015, 05:59

Yes, you've nailed it.

Well done.

X

Yes, you've nailed it.
Well done.

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