# Thread: Difficult variable to solve for. includes hyperbolic cos.

1. ## Difficult variable to solve for. includes hyperbolic cos.

I have the equation y = 1/k * ln(cosh(SQRT(g*k)*t))

My goal is to solve for k. This is for aerospace engineering and "k" includes a variable that I need.

I have rearranged two ways already:
1) k = (acosh2(eyk))/(g*t2)

2) k = ln(cosh(SQRT(g*k)*t))/y

I have NO IDEA as I am only a freshman. How do I get k to a single side? I would greatly appreciate help with this.

Best regards,
Dwight

2. ## Re: Difficult variable to solve for. includes hyperbolic cos.

You will not be able to get an explicit expression for k.

3. ## Re: Difficult variable to solve for. includes hyperbolic cos.

How can I remotely solve for it? I have MathCad available for use; however, we are expected to do this and I don't know where to start.

4. ## Re: Difficult variable to solve for. includes hyperbolic cos.

That depends, do you have values of y and t to put in?

5. ## Re: Difficult variable to solve for. includes hyperbolic cos.

yes I do. I have a table of data from an accelerometer.

6. ## Re: Difficult variable to solve for. includes hyperbolic cos.

You could try to use something like Newton's method...