# Solving E&M Problem: Need Help Writing sinh(...) as a Product of p & k

• NeoDevin
In summary, the conversation discusses a problem in E&M where solving an equation depends on rewriting sinh(\sqrt{p^2 + k^2} \pi) as a product of two functions. The speaker suggests trying to use the Taylor expansion of sinh, but doubts it can be split in that way due to it being a transcendental equation. They also mention the possibility of separating it at an earlier stage of the problem.

#### NeoDevin

I'm trying to solve a problem in E&M, and I got an equation which depends on p and q, which I can solve provided I can write $sinh(\sqrt{p^2 + k^2} \pi)$ as a product of a function of p, with a function of k. If I can do that, I can solve the problem, but I don't know how to do that part (or if it's even possible). Any ideas?

I would try writing the Taylor expansion of sinh and see if that gets you anywhere. However, I don't think you can split it up like that...

Most likely it's a transcendental equation (since sinh is a transcendental function) that can't be solved analytically... Sad situation.

I think if you look at an earlier stge of the problem, you may be able to separate there.

## 1. How do I write sinh(...) as a product of p and k?

To write sinh(...) as a product of p and k, you can use the identity sinh(x) = (e^x - e^-x)/2. Then, you can factor out a k from the numerator to get k(e^x - e^-x)/2. Finally, you can use the identity e^x - e^-x = 2sinh(x) to get the final form of p*sinh(x), where p = k/2.

## 2. Can I use other identities to write sinh(...) as a product of p and k?

Yes, in addition to the identity mentioned above, there are other identities that can be used to write sinh(...) as a product of p and k. These include sinh(x) = (e^x + e^-x)/2 and sinh(x) = (e^2x - 1)/(2e^x).

## 3. Why is it important to write sinh(...) as a product of p and k?

Writing sinh(...) as a product of p and k can be useful when solving E&M problems because it allows you to simplify equations and make them easier to solve. It also helps to identify the role of p and k in the equation and their individual contributions to the overall solution.

## 4. Can sinh(...) be written as a product of p and k for all values of x?

No, sinh(...) can only be written as a product of p and k for specific values of x. This is because sinh(...) is a function that is defined only for real numbers, so the identity used to write it as a product may not hold for all values of x.

## 5. Is there a general formula for writing sinh(...) as a product of p and k?

Yes, there is a general formula for writing sinh(...) as a product of p and k. It is sinh(x) = p*sinh(kx), where p and k are constants. However, the specific values of p and k will vary depending on the identity used and the given equation.